Glossary Of Entomology Terms

Glossary Of Entomology Terms: Huge List Of 578 Insect Terms

This is a collection of Terminology, Entomological and Arthropodal (See Insects or Arthropods) in nature. Some of which you will find used on the other pages of this site, but I have included a lot more terms than I have been able to use in the pages of this site. I hope you find them useful.

It Does Not Contain Any Animal Names, Insect or otherwise, and is Not a Checklist of any sort

If you have a word you think should be here and isn’t please let me know.
If you need a more in-depth resource than this, you need a proper Entomological Dictionary.

Also, if you’re in search of more knowledge, don’t forget to check out our page on Entomology Books.



Abdomen. The hindmost of the three main body divisions of an insect.
Acaricide. A chemical employed to kill and control mites and ticks.
Acetylcholine. A substance present in many parts of the body of animals and important to the function of nerves.
Acrostichal Bristles. The two rows of hairs or bristles lying one on either side of the mid-line of the thorax of a true fly.
Active Space. The space within which the concentration of a pheromone or other behaviourally active substance is concentrated enough to generate the required response, remembering that like light and sound pheromones become more dilute the further they radiate out from their source.
Aculeate. (Hymenoptera) Those members of the Hymenoptera which possess a sting.
Acuminate. Tapering to a long point.
Adeagus. The part of the male genitalia which is inserted into the female during copulation and which carries the sperm into the female. Its shape is often important in separating closely related species.
Adecticous. Of pupa: referring to the state in which the pupa does not posses movable mandibles, the opposite being Decticous.
Aestivation. Summer dormancy, entered into when conditions are unfavourable for active life i.e. it is too hot or too dry.
Age Polyethism. The regular changing of roles of colony members as they get older.
Air sac. A dilated portion of a trachea
Alar Squama. The middle of three flap-like outgrowths at the base of the wing in various flies.
Alate. Winged; having wings.
Alitrunk. Name given to the thorax and propodeum of ‘wasp-waisted’ hymenopterans.
Allopatric. Two or more forms of a species having essentially separate distributions.
Alternating Generations. When two generations are produced within a life cycle each producing individuals of only one sex, either male first and then female or visa-versa.
Alula. In insects (not birds) the outermost of the three flap-like outgrowths at the base of the wing in various flies: really a part of the wing membrane.
Aldrin. (common name). A synthetic insecticide; a chlorinated hydrocarbon of not less than 95 per cent 1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5,8-dimethanonaphthalene; moderately toxic to mammals, acute oral LD,, for rats 44 mg/kg; phytotoxicity: none when properly formulated, but some crops are sensitive to solvents in certain formulations.
Aliphatic. A term applied to the “open chain” or fatty series of hydrocarbons.
Alkaloids. Substances found in plants, many having powerful pharmacologic action, and characterized by content of nitrogen and the property of combining with acids to form 壮alts’.
Alloparental. When individuals other than the parent assist in the caring for that parents offspring.
Altruistic. Self-destructive. or potentially self-destructive behaviour performed for the benefit of others.
Ambrosia. The fungus cultivated by wood-boring beetles of the family Scolytidae
Ametabola. The insects which develop without metamorphosis, namely the Protura, Thysanura, and Collembola.
Amide. Compound derived from carboxylic acids by replacing the hydroxyl of the -COOH by the amino group, -NH2-.
Amine. An organic compound containing nitrogen, derived from ammonia, NH3, by replacing one or more hydrogen atoms by as many hydrocarbon radicals.
Amino acid. Organic compounds that contain the amino (NH,) group and the carboxyl (COOH) group. Amino acids are the “building stones” of proteins.
Ammonia. A colorless alkaline gas, NH3, soluble in water.
Anal. Pertaining to last abdominal segment which bears the anus.
Anal angle. The small apical area enclosed by the inner and outer margins of the hindwing.
Anal fold. A fold in the inner margin of the hindwing.
Anaplasmosis. Infection with Anaplasma, a genus of Sporozoa that infests red blood cells.
Anasa wilt. A wilt disease of cucurbits caused solely by the feeding of the squash bug, no parasitic microorganism involved.
Androconia. (singula = Androconium) In male butterflies, specialised wing scales (often called scent scales) possessing special glands which produce a chemical attractive to females.
Anemic. Deficient in blood quantity or quality.
Annulate. Formed in ring-like segments or with ring-like markings.
Antenna. (pl., antennae). Pair of segmented appendages located on the head and usually sensory in function – the ‘feelers’.
Antennation. Touching with the antenna
Antenodal Veins. Small cross-veins at the front of the dragonfly or damselfly wing, between the wing base and the nodus.
Anterior. Concerning or facing the front, towards the head.
Antibiosis. An association between two or more organisms that is detrimental to one or more of them.
Anticoagulin. A substance antagonistic to the coagulation of blood.
Anus. The posterior opening of the digestive tract.
Anal veins. The hindmost, or most posterior longitudinal wing veins.
Aorta. The anterior, non-chambered, narrow part of the insect heart which opens into the head.
Apex. The point where the costal vein and the outer margin of the forewing meet.
Apiary. A place where bees are kept, normally a group of hives.
Apical. At or concerning the tip or furthest part of any organ: apical cells, for example are at the wing-tip.
Apical area Of the forewing, the area just inside of and contiguous with the apex.
Appendage. Any limb or other organ, such as an antenna, which is attached to the body by a joint
Appendix. In insects, a short vein, especially a short continuation after the main vein has changed direction.
Apterous. Without wings.
Apterygote. Any member of the Apterygota -primitively wingless insects (i.e. insects which have never developed wings during their evolutionary history) in modern classifications this includes the Thysanura but not Collembola Diplura and Protura which are no longer considered insects, but are termed Hexapods instead .
Aquatic. Living in water.
Arachnida. A class of arthropods which include the scorpions, spiders, mites, ticks, among others.
Arboreal. Living in, on, or among trees.
Arista. A bristle-like outgrowth from the antenna in various flies.
Aristate. Bearing an arista or bristle.
Arolium. A small pad between the claws on an insect’s foot. Usually very small, but well developed in grasshoppers and some other insects.
Arrhenoyoky. The production of males from unfertilised eggs.
Arthropoda. A phylum of animals with segmented body, exoskeleton, and jointed legs.
Arthropods. Animals belonging to the phylum Arthropoda.
Asymmetrical. Organs or body parts not alike on either side of a dividing line or plane.
Astelocyttarus. Pertaining to nests, normally those of social wasps, in which the come is attached directly to the support.
Aster yellows. A virus disease of many kinds of plants transmitted by the six spotted leaf hopper and characterized by stunting of plants, sterility, and chlorosis in foliage.
Attractants. Substances which elicit a positive directional response; chemicals having positive attraction for animals such as insects, usually in low concentration and at considerable distances.
Axon. The process of a nerve cell that conducts impulses away from the cell body.


Basal. Concerning the base of a structure – that part nearest the body. Basal cells in Diptera are generally small cells near the base of the wing.
Basitarsus. The Ist segment of the tarsus – usually the largest.
Batumen. A protective layer of propilis or hard cerumen that encloses the nest cavity of a stingless bee colony.
Benzene hexachloride. (chemical name) or BHC. (common name). A synthetic insecticide, a chlorinated hydrocarbon, 1,2,3,4,5,6-hexachlorocyclohexane of mixed isomers; slightly more toxic to mammals than DDT, acute oral LD51 for rats about 200 mg/kg; phytotoxicity: more toxic than DDT, interferes with germination, suppresses growth and reduces yields except at low concentration; certain crop plants, as potato absorb crude BHC with consequent tainting of tubers.
Bilateral symmetry. Similarity of form, one side with the other.Entomology Glossary Beetle On Finger Close Up
Biological control. The control of pests by employing predators, parasites, or disease; the natural enemies are encouraged and disseminated by man.
Bionomics. The study of the habits, breeding, and adaptations of living forms.
Bipectinate. Feathery, with branches growing out oil both sides of the main axis: applied mainly to antennae.
Bisexual. Having two sexes distinct and separate;i.e. a species with males and females.
Bivouac. The mass of army ant workers within which the queen and brood, live while the colony is not on the move.
Bivoltine. Having two generations per year.
Blastogenesis. The origination of different castes, within a species, from the egg by means other than genetic.
Book lung. A respiratory cavity containing a series of leaflike folds.
Bot. The larva of certain flies that are parasitic in the body of mammals.
Brachypterous. With short wings that do not cover the abdomen, used of individuals of a species which otherwise has longer wings.
Bract. A small leaf at the base of the flower.
Brood. In insects, a group of individuals of a given species which have hatched into young or which have become adult at approximately the same time and which live together in a defined and limited area. Often referring to the immature stages of ants bees and wasps.
Bubonic plague. A bacterial disease of rodents and man caused by Pasteurella pestis and transmitted chiefly by the oriental rat flea; marked by chills, fever, and inflammatory swelling of lymphatic glands.
Budding. Colony fission, the creation of new colonies by the departure of one or more reproductive females accompanied by a group of workers specifically to establish a new colony.
Bursa Copulatrix. That part of the female genitalia which receives the aedeagus and sperm during copulation. Its structure is often important in separating closely related species.



Caecum. (pl., caeca). A sac or tubelike structure open at only one end.
Calcareous. Referring to soils or rocks, possessing those elements which result in alkaline or basic reactions.
Callow. Newly eclosed workers in social insect colonies whose exoskeletons are still soft and whose colour has not fully matured.
Callus. A rounded swelling: applied especially to swollen regions at the front or back of the thorax in various flies.
Calypter. Innermost of the three flap-like outgrowths at the base of the wing in various flies. Also known as the thoracic squama, it generally conceals the haltere.
Calyptodomous. Of the nests of wasps, referring to those which are surrounded by an envelope.
Campodeiform. (applied to a larva) Grub-like, flattened and elongated with well-developed legs and antennae. Many beetle larvae are of this type, and so are those of the lacewings.
Capitate. With an apical knob like enlargement.
Capitulum. Head like structure of ticks which bears the feeding organs.
Carabiform larva. A larva shaped like the larva of a carabid beetle, that is etiolate, flattened, and with well-developed legs; with no filaments on the end of the abdomen.
Carbohydrate. Any of a group of neutral compounds made up of carbon, hydrogen, and oxygen; for example, sugar, starch, cellulose.
Cardo. The basal segment of the maxilla or secondary jaw.
Carina. A ridge or keel.
Carnivorous. Preying or feeding on animals.
Castes. Groups of individuals that become irreversibly behaviorally distinct at some point prior to reproductive maturity. One of three or more distinct forms which make up the population among social insects. The usual three castes are queen, drone (male), and worker. The termites and some of the ants have one or more soldier castes as well.
Caterpillar. The larva of a moth, butterfly, or saw-fly.
Catfacing. The injury caused by the feeding of such insects as plant bugs and stink bugs on developing fruit which results in uneven growth and a deformed mature fruit.
Cauda. The pointed end of the abdomen in aphids.
Caudal. Concerning the tail end.
Cell. An area of the wing bounded by a number of veins. A cell is closed if it is completely surrounded by veins and open if it is bounded partly by the wing margin.
Cellulose. An inert carbohydrate, the chief component of the solid framework or woody part of many plants.
Cement layer. A thin laver on the surface of insect cuticles formed by the hardened secretion of the dermal glands.
Cephalic. Of or pertaining to the head.
Cephalothorax. A body region consisting of head and thoracic segments, as in spiders.
Cerci. (singular: cercus) The paired appendages, often very long, which spring from the tip of the abdomen in many insects.
Cerumen. A mixture of wax and propolis used by social bees in nest construction.
Cervical. Concerning the neck region, just behind the head.
Chaetae. Stiff hairs or bristles (singular: chaeta).
Chaetotaxy. The arrangement of the bristles or chaetae on an insect: especially important in the classification of the Diptera, Collembla and several other groups.
Chelicera. (pl., chelicerae). The anterior pair of appendages in arachnids, the fangs.
Chigger. The parasitic larva of trombiculid mites.
Chitin. The tough horny material, chemically known as a nitrogenous polysaccharide, which makes up the bulk of the insect cuticle, also occurs in other arthropods.
Chorion. The inner shell or covering of the insect egg.
Chromosomes. At cell division the dark-staining, rod-shaped structures which contain the hereditary units called genes.
Chrysalis. The pupa of a butterfly.
Ciliated. Bearing minute hairs (cilia).
Cladogram. A diagram showing nothing more than the sequence in which groups of organisms are interpreted to have originated and diverged in the course of evolution.
Class. A division of the animal kingdom lower than a phylum and higher than an order, for example the class Insecta.
Clavate. Club-shaped, with the distal end swollen: most often applied to antennae.
Claustral Foundation. A way of setting up of a new colony by a queen, or king and queen in the termites, which involves her/them being sealing her/themselves a way in a small chamber and raising the first group of workers entirely (or almost so) on stored body reserves (fat and often the flight muscles).
Clavus. Posterior part of the forewing of of heteropteran bugs.
Cleptoparasitism. Where one female uses the resources and nest of another individual (of either the same or a different species) to provide for her young thus usurping the owners efforts and preventing her from using them.
Cline. A progressive, usually continuous change in one or more characters of a species over a geographic or altitudinal range.
Club. The thickened terminal (farthest from the head) end of the antennae.
Clypeus. Lowest part of the insect face, just above the labrum.
Coarctate. (applied to pupae) Enclosed within the last larval skin, which therefore acts as a cocoon and protects the pupa. Such pupae are found in the flies (Diptera, of the sub-order Cyclorrhapha.).
Cocoon. A case, made partly or completely of silk, which protects the pupa in many insects, especially the moths. The cocoon is made by the larva before it pupates.
Colony. A small or large locally isolated population.
Colony. Of social insects, a group which co-operates in the construction of a nest and in the rearing of the young.
Comb. The grouped cells of the nests of social many hymenoptera.
Comb. A group of spines on the leg of an insect specifically used for cleaning other parts of the insects body.
Commensalism. Symbiosis, one or more individuals from two or more species living together such that one benefits but neither loses fitness.
Commissure. A bridge connecting any two bodies or structures on a body.
Communal. Where females of one species co-operate in nest building but not in brood care.
Complete metamorphosis or Complex metamorphosis. Metamorphosis in which the insect develops through four distinct stages, e.g.., ova or egg, larva, pupa, and adult or imago; the wings (when present) develop internally during the larval stage.
Compound eye. An eye consisting of many individual elements or ommatidia each of which is represented externally by a facet.
Connective. A longitudinal cord of nerve fibers connecting successive ganglia.
Contiguous. Touching – usually applied to eyes (see also Holoptic).
Conspecific. Belonging to the same species.
Construction Gland. A gland of wasps producing a size-like substance which enables them to make paper out of wood-pulp.
Copularium. The first chamber built by a newly mated pair of sexual termites.
Corbicula. The pollen basket on the hind leg of many bees, formed by stout hairs on the borders of the tibia.
Corium. The main part of the forewing of a heteropteran bug.
Cornicle. One of the pair of small tubular outgrowths on the hind end of the aphid abdomen.
Corpora allata. A pair of small endocrine glands located just behind the brain.
Cosmopolitan. Occurring throughout most of the world.
Costa. One of the major longitudinal veins, usually forming the front margin of the wing and usually abbreviated to C. The costal margin is the front edge of the wing.
Costal Cell. The cell between the costa and the sub-costal vein.
Costal Fold. A narrow, thin membrane folded back on the upper surface of the costa of the forewing of butterflies, it contains androconia
Coxa. The basal segment of the insect leg, often immovably attached to the body.
Crawler. The active first instar of a scale insect.
Cremaster. The cluster of minute hooks (sometimes just one larger hook) at the hind end of a lepidopterous pupa: used to grip the pupal support.
Crochets. (Pronounced crow-shays). Hooked spines at tip of the prolegs of lepidopterous larvae.
Crop. The dilated section of the foregut just behind the esophagus.
Cross-vein. A short vein joining any two neighboring longitudinal veins.
Cryptic. Colouring and or pattern adapted for the purpose of protection from predators or prey by concealment.
Cryptobiotic. Leading a hidden or concealed life.
Cubitus. One of the major longitudinal veins, situated in the rear half of the wing and usually with 2 or 3 branches: abbreviated to Cu.
Cuneus. A more or less triangular region of the forewing of certain heteropteran bugs, separated from the corium by a groove or suture.
Cursorial. Adapted for running.
Cuspidal. Two segments of curved lines meeting and terminating at a sharp point.
Cuticle. The outer noncellular layers of the insect integument secreted by the epidermis.
Cyclorrhaphous Diptera. The group of flies which emerge from the puparium through a circular opening at one end of the puparium. These flies belong to the more advanced families.
Cytology. The study of cells and there functioning.



DDT. (common name). A widely used synthetic insecticide; a chlorinated hydrocarbon, dichloro diphenyl trichloroethane.
Dealate. Wingless as a result of the insect casting or breaking off its own wings, as in newly mated queen ants and termites.
Decticous. Of pupa: referring to the state in which the pupa possesses movable mandibles which can be used for biting, the opposite being Adecticous.
Dengue. (pronounced deng’e). A virus disease of man marked by severe pains in head, eyes, muscles, and joints and transmitted by certain mosquitoes.
Dentate. Toothed, possessing teeth or teeth like structures.
Denticulate. Bearing very small tooth-like projections.
Deutonymph. The third instar of a mite.
Diapause. A period of suspended animation of regular occurrence in the lives of many insects, especially in the young stages.
Diaphragm. A horizontal membranous partition of the body cavity.
Differentiation. Increase in visible distinctive morphology.
Dimorphic. Occurring in two distinct forms.
Dimorphism. A difference in size, form, or color, between individuals of the same species, characterizing two distinct types.
Discal. The central portion of a wing from the costa to the inner margin.
Discal Cell. Name given to a prominent and often quite large cell near the middle of the wing. The discal cell of one insect group may not be bounded by the same veins as that of another group.
Distad. In a direction away from the body.
Distal. Concerning that part of an appendage furthest from the body.
D.N.A. An abbreviation for Dioxyribonucleic Acid a large molecule which stores the data in our genes in the form of a 3 character code. D.N.A. is a self replicating molecule.
Dorsal. On or concerning the back or top of an animal.
Dorsal Nectary Organ. In the larvae of many species of Lycaenidae (Blue Butterflies) a gland located in the dorsal region of the 7th abdominal segment, it secretes a sweet substance which is attractive to ants.
Dorsal ocellus. The simple eye in adult insects and in nymphs and naiads.
Dorsal shield. The scutum or sclerotized plate covering all or most of the dorsal surface in males and the anterior portion in females, nymphs, and larvae of hard-backed ticks.
Dorso-central Bristles. The 2 rows of bristles running along the thorax of a fly on the outer side of the acrostichal bristles.
Dorso-lateral. Towards the sides of the dorsal (upper) surface.
Dorso-ventral. Running from the dorsal (upper) to the ventral (lower) surface.
Dorsum. The upper surface or back of an animal.
Drone. The male honey bee.
Dulosis. The act of slave making in ants, a species which makes a slave of another is often referred to as Dulotic.



Ecdysis. The moulting process, by which a young insect changes its outer skin or pupal case.
Eclosion. Emergence of the adult or imago from the pupa
Ectoderm. The outer embryological layer which gives rise to the nervous system, integument, and several other parts of an insect.
Ectohormone. A substance secreted by an animal to the outside of its body causing a specific reaction, such as determination of physiological development, in a receiving individual of the same species.
Ectoparasite. A parasite that lives on the outside of its host.
Egg pod. A capsule which encloses the egg mass of grasshoppers and which is formed through the cementing of soil particles together by secretions of the ovipositing female.
Elateriform larva. A larva with the form of a wireworm; i.e. long and slender, heavily sclerotized, with short thoracic legs, and with few body hairs.
Elbowed Antenna. Antenna, particularly of ants, in which there is a distinct angle between two of the segments – usually between the 1st and 2nd segments, in which case the 1st segment is usually much longer than the others.
Elytron. (plural elytra) The tough, horny forewing of a beetle or an earwig (See also Hemi-elytron)
Emarginate. With a distinct notch or indentation in the margin.
Emery’s Rule. The rule resulting from the observation that species of social parasite are very closely related to their host.
Embolium. A narrow region along the front margin of the forewing in certain heteropteran bugs: separated from the rest of the corium by a groove or suture.
Empodium. An outgrowth between the claws of a fly’s foot: it may be bristle-like.
Endemic. Restricted to a well defined geographical region.
Endocrine. Secreting internally, applied to organs whose function is to secrete into blood or lymph a substance which has an important role in metabolism.
Endocuticle. The innermost layer of the cuticle.
Endoparasite. A parasite which lives inside its host’s body. Most of the ichneumons, are endoparasites during their larval stages.
Endopterygote. Any insect in which the wings develop inside the body of the early stages and in which there is a complete metamorphosis and pupal stage.
Entomogenous. Growing in or on an insect, for example certain fungi.
Envelope. The carton or wax outermost later of the nest of a social insect, particularly those of wasps.
Enzyme. An organic catalyst, normally a protein formed and secreted by a living cell.
Epicuticle. The thin, non-chitinous, surface layers of the cuticle.
Epidermis. The cellular layer of the integument that secretes or deposits a comparatively thick cuticle on its outer surface.
Epigaeic. Living or foraging primarily above ground, compared to Hypogaeic the opposite.
Epimeron. The posterior part of the side wall of any of the three thoracic segments.
Epinotum. The first abdominal segment when it is fused with the last thoracic one, relating to the higher thin waisted hymenoptera. Also called a propodeum.
Epipharynx. A component of many insect mouth-parts which is attached to the posterior surface of the labrum or clypeus. In chewing insects it is usually only a small lobe, but in the fleas it is greatly enlarged and used for sucking blood.
Epiproct. An appendage arising from the mid-line of the last abdominal segment, just above the anus. In the bristletails and some mayflies it is very long and forms the central ‘tail’
Episternum. The anterior part of the side wall of any of the three thoracic segments.
Epithelium. The layer of cells that covers a surface or lines a cavity.
Ergatogyne. Any female member of a eusocial group whose morphological development is somewhere between that of a worker and a queen.
Eruciform. (applied to a larva) Caterpillar like; more or less cylindrical with a well developed head and stumpy legs at the rear as well as the true thoracic legs. The caterpillars of butterflies and moths are typical examples.
Eusocial A species which lives in a society such that individuals of the species cooperate in caring for the young, which not all of them have produced; there is a reproductive division of labor, with more or less sterile individuals working on behalf of fecund individuals; and there is an overlap of at least two generations in life stages capable of contributing to colony labor, so that offspring assist parents during some period of their life.
Exarate Pupa. A pupa in which all the appendages, legs etc., are free and capable of movement.
Excavate. Hollowed out: applied to the coxae of many beetles, which are hollowed out to receive the femora when the legs are folded.
Excretion. The elimination of the waste products of metabolism.
Exocuticle. The hard and usually darkened layer of the cuticle lying between the endocuticle and epicuticle.
Exoskeleton. Collectively the external plates of the body wall.
Exopterygote. Any insect in which the wings develop gradually on the outside of the body, in which there is only a partial metamorphosis and no pupal stage.
Exuvia. The cast-off outer skin of an insect or other arthropod.
Eye-cap. Hood formed by the base of the antenna and partly covering the eye in certain small moths.


Facet. The surface of an ommatidium – one of the units making up the compound eye.
Family. A taxonomic subdivision of an order, suborder, or superfamily that contains a group of related subfamilies, tribes and genera. Family names always end in -idae.
Fascicle. A small bundle; the bundle of piercing stylets of insects with piercing sucking mouthparts.
Femur. The 3rd (counting out from the body) and often the largest segment of the insect leg.
Filament. A thread-like structure, especially one at the end of an antenna.
Filiform. Thread-like or hair-like, applied especially to antennae.
Flabellate. With projecting flaps on one side, applied especially to antennae.
Flagellum. The distal (furthest away from the body) part of the antenna, beyond the 2nd segment.
Foregut. The anterior part of the alimentary canal from the mouth to the midgut.
Fossorial. Adapted for digging.
Foveola. (pl. foveolae) One of the paired depressions on each side of the vertex in grasshoppers.
Frenulum. The wing-coupling mechanism found in many moths.
Frons. Upper part of the insect face, between and below the antennae and usually carrying the median ocellus or simple eye. In true flies (Diptera) it occupies almost all of the front surface of the head apart from the eyes.
Frontal Bristles. The two vertical rows of bristles running down the face of a fly from the ocelli to the antennae
Fronto-orbital Bristles. The short row of bristles on each side of a fly’s head between the eye and the frontal bristles.
Furcula. The forked spring of a springtail.
Fuscous. Smokey grey-brown in colour, normally applied to wings.


Galea. the outer branch of the maxillae, the inner one being the lacinia.
Gall. An abnormal growth of a plant caused by the presence in its tissues of a young insect or some other organism. Aphids, gall wasps, and gall midges are among the major gall-causing insects.
Ganglion. A nerve mass that serves as a center of nervous influence.
Gastric caeca. The sac-like diverticula at the anterior end of the midgut.
Gaster. The hymenopteran abdomen – apart from the 1st segment (the propodeum) which is fused to the thorax. The front part of the gaster often forms a narrow waist.
Gena. The cheek – that part of the head below and behind the eye.
Genal Comb. A row of stout spines on the lower border of the cheek of certain fleas.
Generation. The group of individuals of a given species that have been reproduced at approximately the same time; the group of individuals of the same genealogical rank.
Geniculate. Abruptly bent or elbowed (see Elbowed Antenna).
Genital claspers. Organs of the male genitalia which serve to hold the female during copulation.
Genitalia. The copulatory organs of insects and other animals. The shape and arrangement of the genitalia are often used to distinguish closely related and otherwise very similar species.
Genotype. The total genetic character of an organism, i.e. all its D.N.A. or genes
Genus. A group of closely related species (plural: genera). The name of the genus is incorporated into the scientific names of all the member species: Pieris napi and Pieris rapae, for example, both belong to the genus Pieris.
Gill. Breathing organ possessed by many aquatic creatures, including numerous young insects. Insect gills are usually very fine outgrowths from the body and they contain numerous air-tubes, or tracheae. Oxygen passes into the tubes from the water by diffusion.
Girdle. A silken thread supporting the midsection of a pupa.
GIabrous. Without hairs.
Glossa. (plural glossae) One of a pair of lobes at the tip of the labium or lower lip: usually very small, but long in honey bees and bumble bees, in which the two glossae are used to suck up nectar.
Gnathosoma. The anterior part of the body of mites and ticks which bears the mouth and mouthparts.
Gregarious. Living in groups.
Grub. A scarabaeiform larva, i.e. a thick bodied larva with thoracic legs and well developed head; usually sluggish.
Gynandromorph. An individual creature with a mixture of male and female characteristics. One half of the body may be male and the other half female. This is particularly noticeable when it occurs among the blue butterflies and others in which the sexes are differently coloured.


Haemolymph. The blood plasma or liquid part of the blood, though generally synonymous for blood of insects.
Habitus. Body-build, general appearance.
Haltere. One of the club-shaped ‘balancers’ found on each side of the metathorax among the true flies (Diptera). They are the much-modified hind wings.
Hamuli. The minute hooks on the front edge of the hind wing of bees and other hymenopterans, used to link the front and hind wings together. The hook which holds the springtail’s spring in place is also called the hamula.
Haustellate. Adapted for sucking liquids rather than biting solid food.Entomology Glossary Bug On Hand
Heart. The chambered, pulsatile portion of the dorsal blood vessel.
Head. The anterior body region of insects which bears the mouthparts, eyes, and antennae.
Hematophagous. Feeding or subsisting on blood.
Hemi-elytron (plural hemi-elytra). The forewing of a heteropteran bug, differing from the beetle elytron in having the distal portion membranous.
Hemimetabola. Insects with simple metamorphosis, with no pupal stage.
Hemimetabolous. Having an incomplete metamorphosis, with no pupal stage in the life history.
Hermaphroditic. Containing the sex organs of both sexes in one individual.
Heteromerous. (of beetles) Having unequal numbers of tarsal segments on the three pairs of legs.
Hexapod. An animal possessing six legs, more specifically the parent group that contains insects and their close kin.
Hibernation. Dormancy during the winter.
Hindgut. The posterior part of the alimentary canal between the midgut and anus.
Histosiphon. Same as stylostome.The tube formed by the host as a result of the feeding of a chigger secreting salivary fluids, the chigger partially digests skin tissues, which induces the host to form a proteinaceous tube walling off the injury.
Holometabola. The higher insects which have complex metamorphosis.
Homologous. Organs or parts which exhibit similarity in structure, in position with reference to other parts, and in mode of development, but not necessarily similarity of function, are said to be homologous.
Holometabola. The higher insects which have complex metamorphosis.
Holometabolous. Having a complete metamorphosis, with larval and pupal stages in the life history.
Holoptic. With the eyes touching or almost touching on the top of the head: used mainly when describing flies (Diptera).
Holotype. The type specimen of a species is the actual insect from which the original description of that species was produced. If several specimens were used for this purpose, one of them should have been designated as the type. Because the type can be of only one sex, it is usual to designate a certain individual of the opposite sex as the allotype. The original type specimen is then called the holotype. These 奏ype specimens’ are very important in taxonomy and classification.
Homonym. A scientific name which has been given to two different species. When such an instance comes to light one of the species must be given another name.
Hormone. A chemical substance formed in some organ of the body, secreted directly into the blood, and carried to another organ or tissue where it produces a specific effect.
Honeydew. The sweet liquid emitted from the anus of aphids and some other sap sucking bugs.
Host. The organism in or on which a parasite lives; the plant on which an insect or other arthropod feeds.
Humeral Angle. The front basal part of the wing, close to its attachment to the body.
Humeral Vein. A small cross-vein running from the costa to the sub-costa in the humeral (basal) region of the wing.
Hyaline. Clear and colourless, like the wings of most dragonflies.
Hygrophilus. Moisture loving.
Hypermetamorphosis. A type of life history in which the larvae adopts 2 or more distinct forms during its development.
Hyperparasite. A parasitic organism which attacks another parasite.
Hypognathous. Having a vertical head and face with the mouth-parts at the bottom.
Hypopharynx. A component of the insect mouth-parts arising behind the mouth and just in front of the labium or lower lip. Usually short and tongue-like in species with biting jaws, but often drawn out to form a tube for the salivary duct in those species with sucking mouths.
Hypopleural Bristles. A curved row of bristles on the side of the thorax of certain true flies just below and in front of the haltere and just above the base of the hind leg.
Hypostome. In ticks, the median ventral dart-like mouthpart that is immovably attached to basal part of the capittilum.
Hysterosoma. In mites, the posterior part of the body when there is a demarcation of the body between the second and third pair of legs.


lmago. The adult insect (Plural imagines)
Incomplete metamorphosis or Simple metamorphosis. Metamorphosis in which the wings (when present) develop externally during the immature stage and there is no prolonged resting stage (i.e. pupa) preceding the last molt; stages included are the egg, nymphal, and adult. Also called gradual or partial metamorphosis, and paurometabolous development.
Inquiline. A creature that shares the home of another species without having any obvious effect on that species.
Insecta. A ‘class’ of the ‘phylum’ Arthropoda, distinguished by adults having three body regions: head, thorax, and abdomen; and by having the thorax three-segmented with each segment bearing a pair of legs.
Instar. The stage in an insect’s life history between any two moults. A newly-hatched insect which has not yet moulted is said to be a first-instar nymph or larva. The adult (imago) is the final instar.
Integument. The insect’s outer coat.
Intermediate host. The host which harbors the immature stages or the asexual stages of a parasite, a separate organism to that which harbours the sexual stage.
Intercalary Vein. An additional longitudinal vein, arising at the wing margin and running inwards but not directly connected to any of the major veins.


Joint. Strictly speaking, an articulation between neighbouring parts, such as the femur and tibia of the leg, but the word is commonly used as a synonym of segment – meaning any of the divisions of the body or its appendages.
Johnston’s organ. A sense organ located in the second antennal segment of many insects and particularly well developed in male mosquitoes and certain other Diptera.
Jugum. A narrow lobe projecting from the base of the forewing in certain moths and overlapping the hind wing, thereby coupling the two wings together.



Keel. A narrow ridge: also called a carina



Labellum. The expanded tip of the labium, used by many flies to mop up surface fluids.
Labial. Concerning the labium.
Labial palpus. (pl., labial palpi). The labial palps, One of the pair of sensory appendages (feeler-like and 2 to 5 segments long) of the insect labium.
Labium. The ‘lower lip’ of the insect mouth-parts, formed by the fusion of two maxilla-like appendages.
Labrum. The ‘upper lip’ of the insect mouth-parts: not a true appendage but a movable sclerite on the front of the head.
Labrum-epipharynx. A mouthpart composed of the labrum and epipharynx and usually elongate.
Lacinia. The inner branch of the maxilla, the outer one being the galea
Lamella. A thin, leaf-like flap or plate, the name being applied to the outgrowths of certain antennae.
Lamellate. Possessing lamellae: applied especially to antennae.
Larva. Name given to a young insect which is markedly different from the adult: caterpillars and fly maggots are good examples.
Lateral. Concerning the sides.
Lateral ocellus. The simple eye in holometabolous larvae. Also called stemma (pl., stemmata).
Lateral oviduct. In insects, one of the paired lateral ducts of the female genital system connected with the ovary.
Life history. Habits and changes undergone by an organism from the egg stage to its death as an adult.
Ligulae. Name given to the lobes at the tip of the labium: usually divided into glossae and paraglossae.


Maggot. A vermiform larva; a larva without legs and without well-developed head capsule.
Malpighian tubes. Excretory tubes of insects arising from the anterior end of the hindgut and extending into the body cavity.
Mandible. The jaw of an insect. It may be sharply toothed and used for biting, as in grasshoppers and wasps, or it may be drawn out to form a slender needle as in mosquitoes. Mandibles are completely absent in most flies and lepidopterans.
Mandibulate. Having mandibles suited for biting and chewing.
Marginal Cell. One of a number of cells bordering the front margin of the wing in the outer region.
Maxilla. (plural maxillae) One of the two components of the insect mouth-parts lying just behind the jaws. They assist with the detection and manipulation of food and are often drawn out into tubular structures for sucking up liquids.
Maxillary. Concerning or to do with the maxillae.
Meconium. The reddish fluid ejected by a member of the lepidoptera after emerging from the pupa/chrysalis.
Media. The longitudinal vein running through the central region of the wing in most insects: often the 4th and abbreviated to M.
Median oviduct. In insects, the single duct formed by the merging of the paired lateral oviducts; this duct opens posteriorly into a genital chamber or vagina.
Membranous. Thin and transparent (in reference to wings); thin and pliable (in reference to integument).
Mesonotum. The dorsal surface of the 2nd thoracic segment – the mesothorax: usually the largest thoracic sclerite.
Mesopleuron. The sclerite or sclerites making up the side wall of the mesothorax.
Mesoscutellum. Hindmost of the three major divisions of the mesonotum, often triangular or shield-shaped: usually abbreviated to scutellum.
Mesoscutum. The middle and usually the largest division of the mesonotum.
Mesosternum. The ventral surface or sclerite of the mesothorax.
Mesothorax. The 2nd segment of the thorax.
Metamorphosis. Name given to the changes that take place during an insect’s life as it turns from a young animal to an adult. These changes may be gradual and not too large, as in the grasshopper, and metamorphosis is then said to be partial or incomplete. On the other hand, the changes may be much greater and they may take place in one big step – as in the butterflies and moths, which change from caterpillars to adults during the pupal stage. Metamorphosis of this kind is said to be complete.
Metanotum. The dorsal surface of the metathorax. It is often very small and its sub-divisions are usually obscured.
Metapleuron. The sclerite or sclerites making up the side wall of the metathorax.
Metasternum. The ventral surface or sclerite of the metathorax.
Metatarsus. The basal segment of the tarsus or foot: usually the largest segment.
Metathorax. The 3rd and last segment of the thorax.
Micropyle. A minute opening or group of openings into the insect egg through which the spermatozoa enter in fertilization.
Microtrichia. Minute hairs projecting from the integument, they are formed around cellular filaments.
Midgut. The middle part of the alimentary canal and the main site of digestion and absorption.
Moniliform. (of antennae) Composed of bead-like segments, each well separated from the next.
Monophagous. Feeding upon only one kind of food, for example one species or one genus of plants.
Moult. To moult is to shed the outer covering of the body – the exoskeleton.
Myiasis.Infestation of the body by the larvae of flies.



Naiad. An aquatic, gill-bearing nymph.
Nasutus. (pl., nasuti). A type of soldier caste in certain termites; this form bears a median frontal rostrum through which it ejects a defensive fluid; the jaws are small or vestigial.
Nectar. The sugary liquid secreted by many flowers.
Nectary. A floral gland which secretes nectar.
Neurone. The entire nerve cell including all its processes.
Nit. The egg of a louse.
Nocturnal. Active at night.
Nodus. The kink or notch on the costal margin of the dragonfly wing. The name is also used for the strong, short cross-vein just behind the notch.
Notaulix. One of a pair of longitudinal grooves on the mesonotum of certain hymenopterans, dividing the mesonotum into a central area and two lateral areas (plural notaulices)
Notopleuron. A triangular area on the thorax of certain flies, just behind the humeral callus and occupying parts of both dorsal and lateral surfaces.
Notum. The dorsal or upper surface of any thoracic segment: usually prefixed by pro-, meso-, or meta- to indicate the relevant segment.
Nucleus. The spheroid body within a cell that has the major role in controlling and regulating the cell’s activities and contains the hereditary units or genes.
Nurse cells. Cells that are located in the ovarian tubes of certain insects and that furnish nutriment to the developing eggs.
Nymph. Name given to the young stages of those insects which undergo a partial metamorphosis. The nymph is usually quite similar to the adult except that its wings are not fully developed. It normally feeds on the same kind of food as the adult.


Obtect Pupa. A pupa in which the legs and other appendages are closely appressed to the rest of the body and not capable of free movement – as in the butterfly chrysalis.
Occipital Suture. A groove running round the posterior region of the head of some insects and separating the vertex from the occiput. On the sides of the head the same groove marks the posterior boundary of the cheeks or genae.
Occiput. Hindmost region of the top of the head, just in front of the neck membrane. In some insects it is separated from the vertex by the occipital suture, but it is not usually present as a distinct plate or sclerite.
Ocellar Bristles. Bristles arising around or between the ocelli in various flies.
Ocellar Triangle. A triangular area, usually quite distinct from the rest of the head, on which the ocelli of true flies are carried.
Ocellus. (Plural Ocelli) One of the simple eyes of insects, usually occurring in a group of three on the top of the head, although one or more may be absent from many insects.
Oesophagus. The narrow part of the alimentary canal immediately posterior to the pharynx and mouth.
Ommatidium. (pl., ommatidia). One of the units which make up the compound eyes of arthropods.
Ootheca. (pl., oothecae). An egg case formed by the secretions of accessory genital glands or oviducts, such as the purse-like structure carried around by cockroaches or the spongy mass in which mantids lay their eggs
Oral Vibrissae. The pair of large bristles just above the mouth in certain flies: usually simply called vibrissae.
Order. A subdivision of a class or subclass containing a group of related families. Organophosphates. Organic compounds containing phosphorous; an important group of synthetic insecticides belong to this class of chemicals.
Oribatid mite. A mite belonging to the Oribatei, a large unit of mites containing about 35 families in the suborder Sarcoptiformes.
Oviparous. Producing eggs which are hatched outside the body of the female.
Ovipositor. The tubular or valved egg-laying apparatus of a female insect: concealed in many insects, but extremely large among the bush-crickets and some parasitic hymenopterans.
Ovoviviparous. Producing living young by the hatching of the egg while still within the female.


Palp. A segmented leg-like structure arising on the maxilla or labium. Palps have a sensory function and play a major role in tasting food.
Paraglossa. One of a pair of lobes at the outer edges of the tip of the labium: with the central glossae, the paraglossae make up the ligula.
Paraproct. One of the 2 lobes bordering the sides of the anus.
Parasite. An organism that spends all or part of its life in close association with another species, taking food from it but giving nothing in return. Ectoparasites live on the outside of their hosts, while endoparasites live inside the host’s body.
Parthenogenesis. A form of reproduction in which eggs develop normally without being fertilised. This is the usual method of reproduction among some stick insect species and among some generations of gall wasps and aphids.
Pathogenic. Giving origin to disease.
Pecten. A comb-like structure found at the base of the antenna in some insects.
Pectinate. Having branches which arise from the main axis like the teeth of a comb: usually applied to antennae.
Pedicel. The 2nd antennal segment: the name is also given to the narrow waist of an ant.
Pedipalp. The second pair of appendages of an arachnid, used to crush prey.
Petiolate. Attached by a narrow stalk.
Petiole. The narrow waist of bees and wasps and some other hymenopterans: often known as the pedicel when referring to ants.
Pharynx. The anterior part of the foregut between the mouth and the esophagus.
Pheromone. A substance secreted by an animal which when released externally in small amounts causes a specific reaction, such as stimulation to mate with or supply food to a receiving individual of the same species.
Phoresis. The usage by one animal of another soley as a means of transport, i.e. certain mites on various other insects.
Phylum (pl., phyla). A major division of the animal kingdom, containing various suborders and classes etc.
Phytophagous. Feeding upon plants.
Phytotoxic. Poisonous to plants.
Platyform larva. A very flattened larva.
Plumose. Feather-like, as in plumose antennae
Pictured.. A term used to describe wings, especially among the Diptera, which have dark mottling on them.
Pilose. Densely clothed with hair.
Pleural. Concerning the side walls of the body.
Pleural Suture. A vertical or diagonal groove on each of the thoracic pleura, separating the episternum at the front from the epimeron at the back.
Pleuron. The side wall of a thoracic segment.
Plumose. With numerous feathery branches: applied especially to antennae.
Pollen. The mass of microspores or male fertilizing elements of flowering plants.
Pollen Basket. The pollen-carrying region on the hind leg, of a bee: also known as the corbicula.
Pollinate. To transfer pollen grains from a stamen to a stigma or ovule of a plant.
Polyembryony. The production of several embryos from a single egg, as in some chalcids.
Polyphagous. Feeding on a variety of plants and or animals.
Porrect. Extending horizontally forward: applied especially to antennae.
Posterior. Concerning or facing the rear.
Postmentum. The basal region of the labium.
Postscutellum. A small division of the mesonotum just behind the scutellum: usually very small or absent, but well developed in certain flies.
Post-vertical Bristles. A pair of bristles – divergent, parallel, or crossing – on the back of the head of various flies, some way behind the ocelli.
Pre-apical. Arising just before the tip: many flies. for example, have pre-apical bristles just before the tip of the tibia.
Precostal area. The area in front of , or to the fore of the costa.
Predaceous. Preying on other animals.
Predator. An animal that attacks and feeds on other animals, usually smaller and weaker than itself.
Prementum. The distal region of the labium, from which spring the labial palps and the ligula.
Preovipositional period. The period between the emergence of an adult female and the start of its egg laying.
Prepupa. The last larval instar after it ceases to feed; often it takes on a distinctive appearance becoming quiescent and rather shrunken, and often looks dead.
Presumptive organization. Arrangement of cells in the embryo into groups which in normal development become a particular organ or tissue.
Pretarsus. In insects the terminal segment of the leg bearing the pretarsal claws.
Primary reproductives. Those members of a social group of insects whose primary role is reproduction, (often the founders of the colony). Compared to secondary reproductive who may produce some young but are primarily involved in some other activity.
Proctodeal valve. In insects, a valve in the anterior end of the hindgut that serves as an occlusor mechanism.
Proboscis. Name given to various kinds of sucking mouths in which some of the mouth-parts are drawn out to form tubes.
Prognathous. Having a more or less horizontal head, with the mouth-parts at the front.
Proleg. One of the fleshy, stumpy legs on the hind region of a caterpillar.
Pronotal Comb. A row of stout spines on the hind margin of the pronotum of certain fleas.
Pronotum. The dorsal surface or sclerite of the 1st thoracic segment.
Propodeum. The I st abdominal segment in the hymenopteran group known as the Apocrita: it is completely fused with the thorax.
Propupa. In thrips, the next to the last nymphal instar in which the wing pads are present and the legs short and thick. Also in male scale insects.
Prosternum. Ventral surface of the 1st thoracic segment.
Proterosoma. In mites, the anterior part of the body when there is a demarcation of the body between the second and third pair of legs.
Prothoracic gland. One of a pair of endocrine glands located in the prothorax near the prothoracic spiracles.
Prothorax. The 1st or anterior thoracic segment.
Protonymph. The second instar of a mite.
Proventriculus. The posterior section of the foregut.
Pseudoscorpions. Small arachnids, seldom over 5 mm. long, scorpion-like in general appearance but without sting.
Pseudovipositor. The slender tube to which the posterior part of the abdomen is reduced in the female of certain insects.
Proximal. Concerning the basal part of an appendage – the part nearest to the body.
Pruinose Covered with a powdery deposit, usually white or pale blue: especially applied to Odonata.
Pterostigma. A small coloured area near the wing-tip of dragonflies, bees, and various other clear-winged insects: also called the stigma.
Pterygote. Any member of the sub-class Pterygota, which includes all winged and some secondarily wingless insects.
Ptilinum. In Diptera an organ that can be inflated to a bladder-like structure and thrust out through a frontal suture of the head at the time of emergence from the puparium.
Pubescent. Covered with short, soft hair
Pulvillus. The little pad beneath each claw on the foot of a fly.
Punctate. Covered with tiny pits or depressions, like the elytra of many beetles and the thoraxes of many hymenopterans.
Pupa. (pl., pupae). The 3rd stage in the life history of butterflies and other insects undergoing a complete metamorphosis during which the larval body is rebuilt into that of the adult insect a non-feeding and usually inactive stage.
Puparium. (pl., puparia). The barrel-shaped case which conceals the pupa of the house-fly and many other true flies. It is formed from the skin of the last larval instar.
Pupate. To turn into and exist as a pupa.
Pupiparous. Insects which give birth to fully-grown larvae which pupate almost immediately are said to be pupiparous. The main examples are various blood-sucking flies.


Quadrilateral. A cell near the base of the damselfly wing, whose shape is important in separating the families.
Queen cell. The special cell in which a queen honey bee develops from egg to the adult stage.


Race. A variety of a species; a subspecies.
Radial Sector. The posterior of the two main branches of the radius, usually abbreviated to Rs. It usually has several branches of its own.
Radius. One of the main longitudinal veins, running near the front of the wing and usually the 3rd and abbreviated to R. It gives off a posterior branch – the radial sector – and the smaller branches of these veins are numbered R1, R2, etc.
Raptorial. Adapted for seizing and grasping prey, like the -front legs of a mantis.
Rectum. In insects, the posterior expanded part of the hindgut, typically pear shaped.
Reticulate. Covered with a network pattern.
Reproductives. In termites the caste of kings and queens in other social insects only the queens.
Rostrum. A beak or snout, applied especially to the piercing mouth-parts of bugs and the elongated snouts of weevils.
Rudimentary. Poorly or imperfectly developed.


Salivary glands. Glands that open into the mouth and secrete a fluid with digestive, irritant, or anticoagulatory properties.
Saprophytic. Living on dead or decaying organic matter.
Scale. A scale insect; a member of the order Homoptera.
Scape. The 1st antennal segment, especially if it is longer than the other segment.
Scarabaeiform. A grub like larva having a thick, soft body with a well-developed head and strong thoracic legs but with no legs on the hind region: often permanently curved into a C. The larvae of the lamellicorn beetles are of this type.
Sclerite. Any of the individual hardened plates which make up the exoskeleton.
Sclerotization. The hardening and darkening processes in the cuticle (involves the epicuticle and exocuticle with a substance called sclerotin).
Scopa. The pollen-collecting apparatus of a bee, whether it be the pollen basket on the leg or a brush of hairs on the abdomen.
Scopula. A small tuft of hairs.
Scorpion. Any member of the arachnid order Scorpionidae; they have an elongate body and a poison sting at the end of abdomen.
Scutellum. The 3rd of the major divisions of the dorsal surface of a thoracic segment: usually obvious only in the mesothorax and very large in some bugs.
Scutum. The middle of the three main divisions of the dorsal surface of a thoracic segment. Also, in ticks, the sclerotized plate covering all or most of the dorsum in males, and the anterior portion in females, nymphs, and larvae of the Ixodidae.
Sebaceous gland. A gland producing a greasy lubricating substance.
Secondary parasite. A parasite on another parasite.
Segment. One of the rings or divisions of the body, or one of the sections of a jointed limb.
Segmentation. The embryological process by which the insect body becomes divided into a series of parts or segments.
Serrate. Toothed like a saw.
Sessile. Attached to one place and unable to move, like many female scale insects.
Seta. (pl., setae). A bristle.
Setaceous. Bristle-like, applied especially to antennae.
Simple eye. An Ocellus.
Simple metamorphosis. Metamorphosis in which the wings (when present) develop externally during the immature stage and there is no prolonged resting stage (i.e. pupa) preceding the last molt; stages included are the egg, nymphal, and adult. Also called gradual or partial metamorphosis, and paurometabolous development.
Skeletal muscle. In insects, a muscle that stretches across the body wall and serves to move one segment on another.
Social. Living in more or less organized communities of individuals.
Soldier. In termites, sterile males or females with large heads and mandibles; they function to protect the colony.
Solitary. Occurring singly or in pairs, not in colonies.
Species. The basic unit of living things, consisting of a group of individuals which all look more or less alike and which can all breed with each other to produce another generation of similar creatures.
Spermatheca. A small sac-like branch of the female reproductive tract of arthropods in which sperm may be stored.
Spermatophore. A packet os sperm.
Spine. A multicellular, thorn like process or outgrowth of the integument not separated from it by a joint.
Spinose. Spiny.
Spiracle. One of the breathing pores – openings of the tracheal system – through which diffusion of gases takes place. They usually occur on the third thoracic segment and all the abdominal.
Spiracular plate. A plate like sclerite next to or surrounding a spiracle.
Spittle. In insects, a frothy fluid produced by the nymphs of spittlebugs (Cercopidae).
Spur. A large and usually movable spine, normally found on the legs.
Spurious Vein. A false vein formed by a thickening of the wing membrane and usually unconnected with any of the true veins.
Squama. Any of the membranous flaps that arise near the base of the wing in many true flies (plural: squamae).
Stadium. (pl., stadia). The time interval between molts in a developing insect.
Stage. A distinct, sharply differentiated period in the development of an insect, e.g., egg stage, larval stage, pupal stage, adult stage; in mites and ticks, each instar.
Stemma. (pl., stemmata). The simple eye in holometabolous larvae. Also called lateral ocellus.
Sternite. The plate or sclerite on the underside of a body segment.
Stigma. A small coloured area near the wing-tip of dragonflies, bees, and various other clear-winged insects: also called the pterostigma.
Stomodeal valve. In insects, the cylindrical or funnel-shaped invagination of the foregut into the midgut.
Striae. Grooves running across or along the body: applied especially to the grooves on beetle elytra.
Striated muscle. Muscle that is composed of fibers with alternate light and dark bands.
Stridulation. The production of sounds by rubbing two parts of the body together: best known in grasshoppers and other orthopterans.
Style. A slender bristle arising at the apex of the antenna.
Style. One of the small paired appendages on the male subgenital plate of some Orthoptera.
Stylet. A needle-like object: applied to the various components of piercing mouthparts and also to a part of the sting of a bee or other hymenopteran.
Stylostome. The tube formed by the host as a result of the feeding of a chigger; in secreting salivary fluids, the chigger partially digests skin tissues, which induces the host to form a proteinaceous tube walling off the injury.
Sub-apical. Situated just before the tip or apex.
Subcosta. Usually the first of the longitudinal veins behind the front edge of the wing, although it is often missing or very faint: abbreviated to Sc.
Sub-imago. Found only among the mayflies, the sub-imago or dun is the winged insect which emerges from the nymphal skin. It is rather dull in colour, but very soon moults again – the only example of a winged insect undergoing a moult – to reveal the imago.
Sub-marginal Cells. Cells lying just behind the stigma in the hymenopteran forewing: important in the identification of bees and sphecid wasps.
Sub-species. A sub-division of a species, usually inhabiting a particular area: visibly different from other populations of the same species but still able to interbreed with them.
Superfamily. A group of closely related families; superfamily names end in -oidea.
Supplementary reproductives. In termites the caste of males and females with short wings, light pigmentation, and small compound eyes. The females lay eggs in the colony supplementing the work of the queen.
Suture. A groove on the body surface which usually divides one plate or sclerite from the next: also the junction between the elytra of a beetle.
Synonym. One of two or more names which have been given to a single species. The earliest name usually (should) takes precedence.
Systemic insecticide. An insecticide capable of absorption into plant sap or animal blood and lethal to insects feeding on or within the treated host.


Tarsus. (pl., tarsi). The insect’s foot: primitively a single segment but consisting of several segments in most living insects.
Tegmen. (plural tegmina) The leathery forewing of a grasshopper or similar insect, such as a cockroach
Tegula. A small lobe or scale overlying the base of the forewing like a shoulder-pad.
Tergite. The primary plate or sclerite forming the dorsal surface of any body segment.
Tergum. The dorsal surface of any body segment.
Thorax. The middle of the three major divisions of the insect body. The legs and wings (if present) are always attached to the thorax.
Tibia. (pl., tibiae) The forth leg segment between the femur and the tarsus.
Totipotency The potential, throughout life, to express the full behavioral repertoire of the population (even if never actually expressed), and the ability to produce offspring like oneself, exhibiting the full behavioral repertoire of the population, without help.
Trachea. (Plural tracheae). One of the minute tubes which permeate the insect body and carry gases to and from the various organs etc. They open to the air at the spiracles.
Transverse Suture. A suture running across the thorax of many flies and dividing the mesonotum into a scutum and a prescutum.
Triangle. A triangular region near the base of the dragonfly wing, often divided into smaller cells.
Triungulin. Name given to the active 1st– instar larva of oil beetles and some of their relatives: they appear to have 3 claws on each foot.
Trochanter. The second segment of the leg, between coxa and femur: often very small and easily overlooked.
Truncate. Ending abruptly: squared off.
Tubercle. A small knob like or rounded protuberance.
Tymbal. The sound-producing ‘drum-skin’ of a cicada.
Tympanum. The auditory membrane or ear-drum of various insects.
Type. The type specimen of a species is the actual insect from which the original description of that species was produced. If several specimens were used for this purpose, one of them should have been designated as the type. Because the type can be of only one sex, it is usual to designate a certain individual of the opposite sex as the allotype. The original type specimen is then called the holotype. These 奏ype specimens’ are very important in taxonomy and classification.


Uric acid. The chief nitrogenous waste of birds, reptiles and insects-; chemically, C,H,N,O,.


Valve. One of the paired components of the ovipositor.
Veins. In insects, the rib like tubes that strengthen the wings.
Vermiform larva. A legless wormlike larva without a well developed head
Venation. The arrangement of veins in the wings of insects. Ventral. Concerning the lower side of the body.
Vertex. The top of the head, between and behind the eyes.
Vestigial. Poorly developed, degenerate or atrophied, more fully functional in an earlier stage of development of the individual or species.
Visceral muscle. A muscle which invests an internal organ.
Vibrissae. The pair of large bristles just above the mouth in certain flies: usually simply called vibrissae.
Viviparous. Bringing forth living or active young instead of laying eggs


Wing pads. The undeveloped wings of nymphs and naiads, which appear as two flat structures on each side.
Woollybear. A very hairy caterpillar belonging to the family Arctiidae, the tiger moths.
Workers. In termites, the sterile males and females that perform most of the work of the colony; they are pale, wingless, and usually lack compound eyes; in social Hymenoptera, females with undeveloped reproductive organs that perform the work of the colony.

X, Y, Z


Gordon Ramel

Gordon is an ecologist with two degrees from Exeter University. He's also a teacher, a poet and the owner of 1,152 books. Oh - and he wrote this website.


  1. Hi Gordon. This list has been a great help for me.

    For wing venation, I am struggling with the following terms. Could you please add them and the definition relating to venation?

    Antefurcal, postfurcal and interstitial.

    1. This is not my area of expertise, if, as a broad generalist, I could be said to have any expertise, but I had to research this. The following definitions come from “The Braconid and Ichneumonid Parasitoid Wasps: Biology, Systematics, Evolution and Ecology” by Donald L.J. Quicke.
      Antefurcal when the anterior junction of a posterior cross vein is basal to the posterior junction of the cross vein that it is routinely nearly opposite to.
      Interstitial when the anterior junction of a posterior cross vein is more or less directly in line with the posterior junction of the cross vein that it is routinely nearly opposite to.
      Postfurcal when the anterior junction of a posterior cross vein is distal to the posterior junction of the cross vein that it is routinely nearly opposite to.

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