Glossary of Entomology and Acarology Terms

Vocabulary practice cards providing definitions for essential anatomical, developmental, and physiological terms in insect and mite biology.

Abdomen

The third of the three main divisions of the body of an insect.

Aculeate

Pointed; also, a member of the order Hymenoptera which possesses a sting.

Aestivation

Summer diapause.

Alate

A winged insect – applied usually to an aphid.

Ambulacrum

The terminal part of the leg of a mite in regular contact with the substratum, consisting mainly of the apotele but also sometimes a pretarsus and a pulvillus.

Amphitoky

Parthenogenetic reproduction in which both male and female offspring are produced from unfertilized eggs.

Anholocyclic

As in aphids, breeding parthenogenetically and viviparously.

Apotele

The articulating sixth segment arising from the tarsal segment of the pedipalp of certain mites.

Arbovirus

A virus spread by an arthropod vector ('arbo' standing for arthropod-borne).

Arolium

A usually very small pad or saclike structure located between the claws of the foot of an insect.

Arrhenotoky

Parthenogenetic reproduction in which only male offspring are produced from unfertilized eggs.

Basitarsus

The basal (and often the largest) segment of the tarsus.

Bivoltine

Having two generations annually.

Campodeiform larva

An elongate, dorsoventrally flattened larva with well-developed antennae and thoracic legs, as in larvae of many lacewings and beetles.

Cephalopharyngeal skeleton

In certain dipterous larvae, the skeletal structure formed from the reduced, retracted head and the mouthparts.

Chaetotaxy

The arrangement (disposition and number) of bristles or setae on the body and appendages - of particular importance in the classification of Diptera and mites.

Chelicera

One of a pair of much modified structures at the tip of the pedipalp, formed or derived from three segments: a basal trochanter, a fixed main section and an articulating terminal apotele.

Colleterial glands

A pair of glands, associated with the female genitalia, which produce a secretion for cementing eggs to the substratum.

Collophore

The ventral tube on the first abdominal segment of a springtail.

Corbiculum

The so-called 'pollen-basket' of a bee.

Cremaster

A small cluster of hooks or spines at the tip of the pupa of a butterfly or moth, often borne on a distinctive outgrowth.

Crochets

Sclerotized hooks found on the abdominal prolegs of most lepidopterous larvae.

Cuneus

The more or less triangular part of the forewing of a heteropteran bug, separated from the corium by a groove or suture.

Dectious pupa

A pupa with sclerotized, articulated mandibles.

Deuterogeny

Having distinct winter and summer forms.

Deutogyne

The 'winter' female in a species of mite exhibing deuterogeny.

Ecdysis

The process of moulting during which the 'old' skin is cast off and replaced by another.

Elytron

The hardened, horny forewing of a beetle and certain other insects.

Holometabolous insect

An insect with complete metamorphosis, i.e. with a pupal stage in the lifecycle.

Honeydew

A sugary fluid excreted through the anus of certain phytophagous Hemiptera, notably aphids, mealybugs, psyllids and scale insects.

Hypermetamorphosis

A kind of life-cycle which includes two or more distinct types of larvae.

Hypognathous

With a vertically directed head and the mouthparts directed ventrally.

Hypopus

The morphologically distinct, often phoretic, dispersal stage of a mite.

Hysterosoma

That part of the idiosoma of a mite lying beyond (posterior to) the sejugal furrow.

Idiosoma

The hinder-most of the two main sections of the body of a mite, bearing the legs.

Imago

The adult stage of an insect.

Inquiline

An animal living in the 'home' (e.g. a gall or a nest) of another and sharing its food.

Malpighian tubules

The thin, blind-ending tubules that arise between the mid-gut and hindgut of an insect, and which are concerned with the regulation of nitrogenous waste, salt and water.

Meconium

The excreta produced by a fullydeveloped insect larva which does not defaecate during its development; also, the excreta discharged by an adult insect on emerging from the pupa.

Obtect pupa

Appendages firmly fastened to the body, as in Lepidoptera.

Ootheca

The purse-like, egg-containing case produced by cockroaches and other Dictyoptera.

Paedogenesis

Parthenogenetic reproduction in which the adult stage is omitted.

Phoresy

The involuntary transportation of one organism by another, without involving parasitism.

Polyembryony

The embryo of a single egg subdividing to give rise, on hatching, to two or more larvae (all of which will be of the same sex).

Prodorsal shield

The more-or-less triangular shieldlike part of an eriophyid mite, anterior to the annulated hysterosoma, which overlies the propodosoma.

Prognathous

With a more or less horizontal head and the mouthparts located anteriorly.

Propodeum

The first abdominal segment in certain Hymenoptera (Apocrita), located in front of the pedicel and thus appearing to be part of the thorax.

Propodosoma

That part of the idiosoma of a mite lying anterior to the sejugal furrow and bearing the first and second pairs of legs.

Protogyne

The 'summer' female in a species of mite exhibing deuterogeny.

Pterostigma

A small pigmented area present towards the tip of an otherwise 'clear' wing of an insect (sometimes also called a 'stigma').

Ptilinum

A small balloon-like structure which is projected temporarily from the front of the head of a young fly to aid its emergence from the puparium.

Pupal paedogenesis

Parthenogenetic reproduction in which the adult stage is omitted from the lifecycle and the 'pupa' (= hemi-pupa) gives rise directly to a 'new' generation of larvae.

Puparium

In higher Diptera: the barrel-shaped structure, formed from the cast-off skin of the fmal-instar larva (exuvium), within which the pupa is formed.

Scarabaeiform larva

A larva with a thick, fleshy (often C-shaped) body and a well-developed head and thoracic legs - exemplified by chafer larvae.

Sclerotization

The process by which the cuticle is hardened and tanned by the formation of the protein sclerotin.

Sejugal furrow

A suture or groove which divides the idiosoma of a mite into the propodosoma and the hysterosoma.

Siphunculus

One of a pair of pores or tube-like structures on the abdomen of an aphid which discharge, for example, alarm pheromones and other defensive secretions.

Stemma

In holometabolous insects, the 'simple' eye (ocellus) of a larva, which is sometimes capable of forming a relatively clear image.

Sternal spatula

A ventrally placed structure present in third-instar larvae of most midges (Cecidomyiidae), formed from the remains of the head capsule and used to burrow into the soil prior to pupation.

Stylophore

The needle-like piercing mouthparts of a mite, formed from the coalesced chelicerae.

Tegmen

The hardened, leathery forewing of a cockroach, grasshopper, etc.

Thelytoky

Parthenogenetic reproduction in which only female offspring are produced.

Thumb-claw

In certain mites, a prehensile structure on the pedipalps, formed from the tibial seta (which forms the claw) and the palpal tarsus (which forms the 'thumb').

Tympanum

The auditory membrane or 'ear' of an insect.

Ventriculus

The main digestive (usually tubular) section of the mid- gut.

Wing pad

The sac-like structure in an insect nymph that is the developing precursor of the adult wing.