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Aphid Glossary

Short explanations of aphidological terms

Browse alphabetically: a b c d e f g h i l m n o p r s t u v x

accessory sensoria:

a small cluster of sensoria (= rhinaria) adjacent to the primary rhinarium on the distal end of the base of the terminal antennal segment.

See also: AphID.

accidental host:

a host plant an aphid accidentally finds itself upon, which enables that species of aphid to survive very poorly, if at all.

Note, accidental host has a similar meaning in parasitology: Wikipedia.


the reproductive organ of a male insect through which sperm from the testes is delivered to the female during copulation.

See also: Amateur Ent. Soc., AphID, Wikipedia.

adelgids (woolly conifer-aphids):

feed on conifers and, whilst closely related to 'true' aphids, have no cauda or siphunculi. The complete life cycle lasts TWO years.


See also: Aphids on World Plants, Wikipedia.


a period of inactivity in summer (as opposed to hibernation, a period of inactivity in winter). In aphids aestivation and hibernation are usually responses to lack of nutrients, rather than temperature.

See also: Amateur Ent. Soc., Wikipedia.


winged individuals. All alates are adult, but not all adults have wings. Not all aphid species produce winged adults, and many do so in response to crowding, nutritional or environmental cues. Note: Alatiform nymphs are sometimes, loosely, described as 'alate'.

See also: Amateur Ent. Soc., AphID, Wikipedia.

alatiform (alatoid):

having some features of a winged (alate) adult. For example immature winged forms with wing buds (usually fourth-instar, or sometimes 3rd instar, nymphs).

alatiform (or alatoid) also refers to adult apterae exhibiting alate features: especially a clearly demarcated head and prothorax, a thickened thorax, or secondary rhinaria on the antennae. Adult apterae with undersized wings are described as brachypterous.

anal plate:

a hardened plate, sometimes also thickened and darkened, ventral to the anus. Only present in adults.

See also: AphID, Wikipedia.

anal vein:

a wing vein in Aphidoidea now known as Cu1b (= the second branch of the first cubital vein) or, occasionally, CuA2. In old literature on Aphidoidea referred to as the first anal vein, A1, or the first discoidal wing vein, d1.

See also: Wikipedia.


having an incomplete lifecycle. Such aphids reproduce parthenogenetically all year round. More exactly: anholocyclic aphids are 'species' which have never been shown to undergo sexual recombination. Note: some aphids are only anholocyclic over part of their geographic range.


describing a ring-like (circumferential) structure such as annular secondary rhinaria in Eriosomatinae.

See also: AphID.

anteclypeus (=anterior clypeus):

the lower part of a divided clypeus, between the postclypeus and the labrum. A cuticular plate (often divided longitudinally into a a pair of plates) on the lower part of the 'face' anterior to the mouthparts of some insects.

antennal tubercles:

(= lateral frontal tubercles) two lumps on the head, each of which bears one antenna.

See also: AphID


immediately anterior to the base of each siphunculus.

Anthocoridae (flower bugs, or pirate bugs):

a family of Hemiptera ('true bugs'). Usually less than 5 mm long, with soft, elongated, flat bodies - often patterned in black and white. Both their nymphs and adults are predatory. They often feed on aphids, and other small arthropods. They sometimes bite humans.

See also: Wikipedia


a family of very small wasps which are aphid parasitoids.

See also: Wikipedia.


commonly known as green-fly or black-fly in the UK, and as plant-lice in the USA. 'True aphids' are members of the Aphididae family, which is the sole member of the Aphidoidea superfamily, in the suborder Sternorrhyncha. The other superfamily in that suborder is the Phylloxeroidea which contains the family Adelgidae and the family Phylloxeridae - both of which are sometimes grouped with, or loosely described as, aphids.

See also: Amateur Ent. Soc., Wikipedia.


a superfamily of Hemiptera within the Sternorrhyncha.
Aphidoidea (sensu Remaudière): includes all living aphid species.
Aphidoidea (sensu Heie): excludes adelgids and phylloxera.
We always use Aphidoidea (sensu Remaudière). If no authority is given, or if you are unsure, check.


a braconid genus of aphid parasitoids. The female wasp normally injects one egg into each aphid nymph.


warning coloration.

For example...

See also: Amateur Ent. Soc., Wikipedia.


individuals lacking wings. Apterous aphids may be immature or adult, but (confusingly) the term apterae is often taken to mean wingless adults.

See also: Amateur Ent. Soc., AphID.


the large bristle attached to the front part of the antennae in some species of Diptera.

See also: Amateur Ent. Soc., Wikipedia.

augmentative control:

pest control by augmenting a naturally-occuring predator, or parasite, population. Note, whilst predators and parasites may control pest numbers, augmentative releases may not improve the degree of that control.


a braconid genus of aphid parasitoids. Has 2 sets of tubercles of various sizes and shapes, on the basis of which it can be separated from the Trioxys genus. e.g. Binodoxys communis, originally endemic to China, was introduced to Hawaii for biological control.


having very short or incompletely-developed wings.

See also: Amateur Ent. Soc., Wikipedia.


a large family of parasitoid wasps. Species are often black-brown with long ovipositors. Most species of aphid parasitoid belong to one of 8 genera: Aphidius, Binodoxys, Diaeretiella, Ephedrus, Lysiphlebus, Pauesia, Praon and Trioxys.

See also: Wikipedia.

capitate hairs:

hairs having a knob-like swelling at their distal end.


a large active family of predatory beetles known as 'ground beetles', most of which have shiny black, or metallic, ridged wing covers. Some carabids can produce nasty secretions to deter predators.

See also: Wikipedia.


a short, tail-like appendage.

See also: AphID

Cecidomyiidae (gall midges):

the larvae of most species in this family cause abnormal plant growth, known as 'galls'. But the larvae of some species are aphid predators. Not to be confused with biting-midges (Ceratopogonidae) whose adults feed on blood, or non-biting midges (Chironomidae) which have aquatic larvae.

See also: Wikipedia.

clarified slide mount (or permanent mount):

a slide-mounted semi-transparent ghost-like aphid outer-skin - obtained after removing the lipids, waxes, internal organs and suchlike, by treating the aphid with (among other things) alcohol and potassium hydroxide. This preparation enables you to see both dorsal and ventral features.

See also: Aphids on World Plants


mouthparts of the Chelicerata: including the arachnids. These jointed mouthparts range from simple hooks, through to articulated scissors / pliers. Some can also inject venom.

See also: Wikipedia.


in Heteroptera, it is the oblong hardened plate (=sclerite) at the base of the inferior margin of the basally-hardened forewing (=hemelytron).


one of the sclerites making up the 'face' of an insect, lying between the labrum and the frons, usually separated from the latter by a groove.

See also: Amateur Ent. Soc., Wikipedia.


a flat border (or margin, or flange) extending either side of an insect's abdomen - in dorsoventrally flat insects, particularly Heteroptera.


the leading edge of the wing (when in flight).

See also: Amateur Ent. Soc., Aphids on World Plants.


first segment of an insect leg. It joins the leg and body.

See also: Amateur Ent. Soc., AphID, Wikipedia.

Coccinellidae (ladybirds, UK; ladybugs, US):

a family of small, mainly predatory, beetles with black legs, heads and antennae. Their wing covers are usually yellow to red with black spots.

See also: Wikipedia.

Chrysopidae (lacewings):

a large family of delicate insects, in the order Neuroptera. The larvae of some species are aphid predators. There are about 85 genera and 1300-2000 species of chrysopid.

See also: Wikipedia.


first instar nymph of an adelgid. Apart from winged forms, the crawler is the only active form of adelgids, and is the stage that actively locates a settling site on the tree.


with perforations like those of a sieve.


concealed (hidden), hard-to-find.

For example...

See also: Amateur Ent. Soc., Wikipedia.


a wing vein in Aphidoidea now known as Cu1a (= the first branch of the first cubital vein) or, occasionally, CuA1. The cubitus is the fifth longitudinal vein from the anterior edge of an insect's wing. In old literature on Aphidoidea referred to as Cu (= the second discoidal wing vein).

cultural control:

pest management by manipulating the growing environment, or by measures such as using resistant plants - as opposed to using insecticides or introducing organisms for biological control.

See also: Wikipedia.


a triangular, wedge-shaped, section at the apex of the thick, leathery part of the hemelytra (the modified forewings of some Heteroptera).

cyclical parthenogenesis:

describes a life cycle in which organisms undergo a single sexually-reproducing generation followed by a number of generations of asexual reproduction.

Dermaptera (earwigs):

Most species of the order Dermaptera are scavengers, but some are predators of other arthropods. Some earwig species are thought to be important aphid predators, for example in orchards.

See also: Amateur Ent. Soc., Wikipedia.


suspended development.

See also: Amateur Ent. Soc., Wikipedia.


a genus with only a single species: Diaeretiella rapae which attacks nearly 100 aphid species - notably Brevicoryne brassicae, Diuraphis noxia, Lipaphis erysimi and Myzus persicae. Diaeretiella rapae has been used for biological control.

See also: Wikipedia.


being ONE of two possible forms. For example, in summer Periphylus californiensis nymphs are dimorphic (of normal or dipausing form) - the diapausing nymphs are known as dimorphs.

dimorphic: having TWO possible morphs in a population. From Greek: di (=2) morphe (=form).

See also: Amateur Ent. Soc.


the back of an insect, corresponding to the spinal surface of vertebrates.


moulting of the insect's cuticle.


See also: Amateur Ent. Soc., Wikipedia.


Except for a few (anholocyclic species) all aphids can lay eggs - primarily in order to survive cold, or food-scarcity. Adelgids and Phylloxerids lay eggs produced sexually or parthenogenetically. 'True aphids' only lay fertilized eggs - unfertilized eggs are very small, and develop directly to live young, which are borne viviparously.


See also: Amateur Ent. Soc., Aphids on World Plants, Wikipedia.


two hardened forewings, notably of Coleoptera (beetles), that function as protective covers for the two posterior flight wings. Heteroptera species ('true bugs') have basally-hardened forewings, known as hemelytra.

See also: Wikipedia.

epicranial suture:

an inverted Y-shaped 'suture' above the facial region extending up to the epicranial part of the head (= forehead); not strictly-speaking a suture but a line along which the head cuticle of the immature insect splits at ecdysis.


lobe or spine between the 2 tarsal claws.

See also: Amateur Ent. Soc.


a braconid genus of aphid parasitoids, with complete forewing venation and 5 closed cells. Ephedrus plagiator has been introduced as a biological control agent of the blue alfalfa-aphid, Acyrthosiphon kondoi.


Permanent reduction to zero, worldwide, as a result of deliberate effort. Eradicate is frequently misused to describe reduction to below detectable limits within a specified geographic area.


aphid on its secondary host.


the outer skin of an arthropod cast-off after a moult. - From the Latin 'exuviae': that which is stripped from a body.

See also: Amateur Ent. Soc., Wikipedia.


upper part of the leg, corresponding to the thigh in humans.

See also: Amateur Ent. Soc., AphID, Wikipedia.


middle-part of the front of the head.

See also: AphID.


progeny of a fundatrix, which is the founding female of a colony. 'Spring migrants' are winged fundatrigeniae of host-alternating aphids.

fundatrix (founding or stem mother):

adult female which has developed from an overwintering fertilized egg.


brownish-gray or dusky color.


female which hatched from eggs laid by an adelgid fundatrix.


the mouth and feeding-parts of mites and ticks (the chelicerae, the pedipalps and, in ticks the hypostome). It is separated from the idiosoma (the main body) by flexible cuticle (the circumcapitular furrow, or suture).

See also: Wikipedia.


modified tubular appendages of the anal region in male and female insects that functions in copulation, oviposition, or stinging - and regarded as modified appendages, usually paired. In aphids they are generally referred to as rudimentary gonapophyses: reduced genitalia consisting of, usually 3 or 4, hair-covered bumps in the hind region of an adult female (sexual or otherwise).

See also: AphID.


the sclerite forming the central portion of the underside of the head = the aphid's 'throat'.

gynoparae (=sexuparae):

parthenogenetic females that bear the sexual generation. In other words: females whose offspring develop to sexual forms. In host alternating species these are the returning migrant alates.


two basally-hardened forewings, of Heteroptera species, that function as protective covers for the two, posterior flight wings. Thick and cornified at the base, and membranous at the apex. Coleoptera species (beetles) have wholly-hardened forewings (elytra) which cover their flight wings.

Hemiptera ('true bugs'):

an order of at least 50,000 insect species. Previously divided into 2 suborders, Heteroptera (shield bugs, bed bugs, assassin bugs, stink bugs) and Homoptera (cicadas, planthoppers, moss bugs, aphids). The Homoptera have been replaced by 3 suborders: Auchenorrhyncha (cicadas, leafhoppers and planthoppers), Coleorrhyncha (moss bugs), and Sternorrhyncha (aphids, adelgids & Phylloxerids, psyllids, scale insects and whiteflies).

See also: Wikipedia.

Heteroptera: ('typical bugs'):

a suborder of 40,000 insect species (within the order Hemiptera) most of which have partially hardened forewings (hetero=different, ptera=wing). The Heteroptera include the bed bugs, assassin bugs, stink bugs, pond skaters, water scorpions and water boatmen.

See also: Wikipedia.


the Nearctic + Palaearctic.

See also: Wikipedia.


having a complete life cycle. Such aphids alternate parthenogenesis with sexual reproduction.


(homo=same, ptera=wing) originally a suborder (of the Hemiptera) sister to the Heteroptera. Currently replaced by 3 suborders: the Auchenorrhyncha (cicadas, leafhoppers & planthoppers), Coleorrhyncha (moss bugs), and Sternorrhyncha (psyllids, scale insects, whiteflies, phylloxerids, adelgids & 'true aphids').

See also: Wikipedia.

host alternation:

regular movement, usually seasonal, between a two distantly-related host plant species: usually a woody (primary) host species, where sexual reproduction may occur, and usually a herbaceous (secondary) host species where reproduction is asexual.


of transparent; amorphous, glass-like appearance.

See also: Wikipedia.


the main body region of a mite - bearing the legs, genitals, anus, plus various tactile and sensory structures. It is usually covered by sclerotized shields and respiratory pores.


adult. An adult insect is known as an imago.

See also: Amateur Ent. Soc., Wikipedia.


developmental stage between each moult. Most aphid species go though 4 nymphal instars before moulting to the adult stage.

For example...

See also: Amateur Ent. Soc., Wikipedia.


often described as the "lower lip" of the insect mouth; in aphids it forms the rostrum and has a dorsal groove in which the stylets run.

See also: Amateur Ent. Soc., Wikipedia.

less-preferred host:

a host species that commonly supports a given species of aphid, but where that species fares less well than when on their preferred host species.

longitudinal veins:

wing veins which fan out from the wing base to its edges, and stiffen the wing. The longitudinal veins are numbered anteriorly to posteriorly: 1' the Costa (C, the wing's leading edge); 2' the Subcosta (Sc); 3' the Radius (R); 4' the Media (M); 5' the Cubitus (Cu); 6' the Anal vein(s) (the anal vein has been lost in Aphididae). These may be branched, fused, absent, or have cross-linking veins. Under the old system for Aphidoidea longitudinal veins were termed discoidal wing veins, and numbered posteriorly to anteriorly.


a braconid genus of aphid parasitoids, comprising more than 20 species, which collectively exploit over 100 aphid species as hosts including a number of important agricultural pests. Within Lysiphlebus two well-defined species-groups are recognised: the fabarum group, and the testaceipes group.


having large wings, or long wings. The opposite of brachypterous (reduced wings).

marginal sclerite:

hardened lateral dorsal plate.

marginal tubercles:

rounded bumps that protrude from the side of the insect's abdominal segments, which are easily confused with spiracles.

See also: AphID,


Part of the mouthparts; the maxillae and mandibles in aphids are modified to form two pairs of long bristle-like stylets.

See also: Amateur Ent. Soc.

media vein (M):

in Aphididae, a wing vein arising from subcostal band between cubitus 1a (Cu1a) and Radial sector (Rs) and extending to the wing margin. The media usually has one or two branches. In old literature it was referred to as the third discoidal wing vein.

median frontal tubercle:

rounded bump midway on the head between the antennal tubercles.

See also:


the upper surface of the middle segment of the thorax (the mesothorax).

See also: Wikipedia.


the posterior part of the mesonotum of an insect.


the middle segment of the thorax, between the prothorax and metathorax.

See also: Wikipedia.


the dorsal exoskeletal plate of the metathorax. The metathorax is the hindmost of three leg-bearing segments in the insect's thorax. Its principal sclerites are the metanotum, the metasternum (ventral), and metapleuron (which lie on either side).

See also: Wikipedia.

Miridae (=capsids):

the largest family (having at least 10,000 species) of the suborder Heteroptera 'true bugs'. Some species are agricultural pests, others are predators.

See also: Wikipedia.


along with ticks, comprise the subclass Acari in the class Arachnida. Mite species are incredibly diverse: Many are microscopic. Some are important decomposers, some are predators, some are parasites.

For example...

See also: Amateur Ent. Soc., Wikipedia.


remains on one host plant species all of the year. Does not move between a woody (primary) host plant, and a herbaceous (secondary host) host plant - either because the aphids are not a host-alternating species, or where there is no known primary host - or the primary host is absent.


in the strict sense monophagous aphids prefer a single hostplant species. In the broader sense, 'monophagous' aphids are restricted to hosts within one or two closely related genera. Aphids are generally monophagous. Even host alternating species, whilst relatively polyphagous in their choice of secondary hosts, are generally monophagous regarding their primary host.


originally from the Greek, morphe, meaning form (= shape). 'Morph' usually denotes a distinct adult body form, occasionally an immature body form, assumed to be one of several distinct alternatives. Morph does NOT denote plastic change, nor metamorphosis - immature aphid instars, and mature aphids, have a discrete set of body forms. Some forms are dictated genetically (=genomorphs), but most are dictated environmentally (=phenomorphs). Caution: whilst 'morph' is in common use, in practice the meaning is imprecise.


See also: Amateur Ent. Soc., AphID, Aphids on World Plants, Wikipedia.


aphid nymphs parasitized by some wasp species die shortly before the wasps emerge. The aphids' swollen, brown body is called a mummy.


North America to northern Mexico, plus Greenland but not Iceland. The fauna is closely related to that of the Palaearctic region.

See also: Wikipedia

neotenic (neoteny):

retention of a juvenile character or characters in adults.

See also: Wikipedia.


the young of an insect which undergoes incomplete metamorphosis.


See also: Amateur Ent. Soc., Wikipedia.

ocular tubercle:

a tubercle, usually on the outer-rear surface of an aphid's compound eye, bearing the triommatidium. Although not universally present, and several other taxa have analagous structures, an ocular tubercle bearing a triommatidium is peculiar to Aphidoidea.

See also: AphID.


a 'simple', single-lens eye.

See also: Amateur Ent. Soc., AphID, Wikipedia.


the region posterior to the vertex on the head.

overflow host:

a less-preferred host host, where aphids may be found when their numbers are very high on the preferred host.


females that produce eggs, not live young.

All 'true aphids' (Aphididae: Aphids, in the strict sense, sensu stricto) only produce eggs by sexual reproduction.

Adelgids and Phylloxerids (which are aphids in the broad sense, sensu lato) only reproduce via eggs. They sometimes produce eggs by sexual reproduction, but mostly do so asexually.

See also: AphID


to lay eggs, not live young.

See also: Amateur Ent. Soc.


complete development of the single embryo within a shell-less egg, taking place within the body of the living sexual female. The larval fundatrix emerges from this membranous egg immediately after deposition.


Europe, northern Africa, the northern and central Arabian Peninsula, and Asia (north of the Himalaya foothills) including China and Japan.

See also: Wikipedia


the terminal (last) section of pedipalp, in some groups modified to form the active part of a pincer.


the penultimate (2nd to last) section of pedipalp, in some groups modified to form the passive part of a pincer.


are parasites which invariably kill their host. Aphid parasitoids are parasitic wasps, of family Braconidae (usually 2-3 mm long) or Aphelinidae (0.6-1.4 mm long), that lay eggs inside aphids (usually the nymphs).
primary parasitoids:
feed upon and develop within an aphid host.
secondary parasitoids:
feed upon and develop within a primary parasitoid. Also termed hyperparasites.

See also: Amateur Ent. Soc., Wikipedia.


able to reproduce without requiring males. Asexual reproduction. Parthenogenesis: from the Greek parthenos (=virgin) + genesis (=creation).

See also: Amateur Ent. Soc., AphID, Wikipedia.


are a braconid genus of aphid parasitoids. Pauesia only use conifer aphids (Cinara) as their host. Pauesia grossa is a parasitoid of the black stem aphid, Cinara confinis, a pest of fir trees.

For example...

See also: Wikipedia.


a pair of appendages either side of the jaws of most arachnids used as sensory organs, for locomotion, or grasping - where the last two segments of palp, the palp-tibia and palp-tarsus form a grasping pincer.

See also: Wikipedia.


around the cauda (the insect's tail-end).


the round plate that surrounds a spiracles. In Acari, peritremes are a system of tubes running from the stigmata into the body - used for gas exchange - analogous to insect tracheae.

Phylloxerids (=Phylloxeridae):

a small family, related to 'true aphids', whose winged forms hold their wings horizontally. They have two subfamilies (Phylloxerininae and Phylloxerinae) and 10 genera. Most species are in 2 genera: Phylloxerina (about 9 species, wax-covered & wingless, mostly with willow as a single-host) and Phylloxera (about 60 species, small & pear-shaped, mostly in Northern USA, on Juglandaceae and/or Fagaceae).

Phylloxera devastratrix is an important pest of pecans.

Daktulosphaira vitifoliae, the sole species of its genus, was a serious grape vine pest in the 19th centuary.

See also: Wikipedia.

polygonal reticulation:

in some aphid species the distal end of their siphunculi have an irregular pattern of polygons, each being 1/3 to 1/6 of the siphuncular width.


able to feed on a wide range of different things. 'Polyphagous aphids' can grow to maturity when feeding upon any one of many host plant species, of at least several genera. In the strict sense, a polyphagous aphid species can reproduce succesfully on plants from at least several families. Very few aphids are genuinely polyphagous, and even highly polyphagous species reproduce poorly (or cannot even feed) on many host species. (Many, if not most, aphids are monophagous.)

For example...

See also: Wikipedia.


the ability to form multiple discrete phenotypes (forms) from a single genotype. As distinct from polymorphism (multiple morphs) in that, for example, aphid males are a distinct sexual form, produced asexually, but are genetically different from their mothers and from sexual females (oviparae).


See also: Amateur Ent. Soc., AphID, Aphids on World Plants, Wikipedia.


location immediately posterior to the base of each siphunculus.


this braconid genus of aphid parasitoids is one of the largest genera of the subfamily Aphidiinae, with more than 50 species described worldwide. Praon parasitoids spin their cocoon UNDER the empty body of the aphid (most other Aphidiines pupate INSIDE the parasitized aphid). Many species are important parasitoids in various agro ecosystems. Praon volucre has been considered as a biological control agent of the pest aphid Uroleucon ambrosiae on lettuce in Brazil.

preferred host:

the species of plant upon which an aphid species is most commonly-found, and which enables it to breed most successfully. Monoecious aphids have only one species of preferred host. Most aphid species have several preferred hosts, usually of one plant genus. Many host alternating species have one preferred primary host, but preferred secondary hosts representing several genera. Few aphids are genuinely polyphagous but, especially when their numbers are high, some aphids raise colonies on (less-suitable) overflow host-plant species - a few accidentals, on unsuitable hosts, may feed but fare very poorly.

See also: Aphids on World Plants

primary host:

The primary host is the plant species upon which a host-alternating aphid species lays its (sexually produced) eggs, from which fundatrices emerge. Many aphid species spend the cooler season on a 'primary' usually-woody host plant, and move to a 'secondary' usually herbaceous host plant for the warmer season.

Host alternating adelgids spend at least one year on the primary host, and at least one on the secondary host. Adelgids lay sexually-produced eggs on their primary host, and parthenogenetically-produced eggs on the secondary host - from which pseudo-fundatrices emerge.

Note: primary host means something quite different to, for instance, parasitologists. See: Wikipedia

primary rhinaria:

these rhinaria are plate-like sensory patches on the (distal) fifth and (proximal) sixth antennal segments of aphids, presumed to be (at least primarily) smell-receptors.

prodorsal shield:

the larger dorsal portion covering the anterior region of a mite's body.

progredientes (plural) (singular = progrediens):

adelgid exules that do not diapause, and moult from the first to second instar with no delay.


a sclerotized structure covering all or part of the dorsal surface of the thorax.

See also: Amateur Ent. Soc.


the ventral plate of the most anterior segment of the thorax.


the tibia of the front leg, the foreleg, or prothoracic leg (the leg connected to the prothorax).

See also: AphID,


the most anterior segment of the thorax - to which are attached the front legs.

See also: Wikipedia.


wingless female adelgid which hatches from eggs produced parthenogenetically by an adelgid gallicola. A 'true' fundatrix hatches from a fertilized egg.


A 'pseudogall' is produced by rolling, folding or crumpling of the leaf without any cellular enlargement or proliferation.

A 'true gall' is an abnormal plant growth caused by cellular enlargement and/or proliferation, due to the action of another organism, which provides that organism with shelter and/or nutrients.


scent glands on the hind tibiae of the ovipara, similar in appearance to rhinaria.

psocids (booklice, barklice, barkflies):

the insect order Psocoptera has 3 suborders containing 41 families and 5,500 species. They are among the most primitive Exopterygota (=hemipteroids) and phytophagous or scavengers, their sister taxon (Phthiraptera) comprises the parasitic lice.

See also: Wikipedia.

psyllids ('jumping plant lice'):

a family (or several families) comprising at least 70 genera of small monophagous plant-feeding insects.

See also: Wikipedia.


(= stigma) a dark pigmented spot on the wing's leading edge and toward the tip.

See also: Amateur Ent. Soc., Aphids on World Plants, Wikipedia.


the middle and hind and segments of the thorax. Bearing, respectively, the fore wings and hind wings.

See also: Wikipedia.


a covering of fine wax powder.

Radial sector: (Rs, RS)

an insect wing vein. Rs is the first posterior branch of the Radius (R, the radial vein - the first anterior branch of the Radius being R1). Rs is also known as the stigmal vein.

See also: Wikipedia.

reserve host:

an aphid species' less-preferred host, which enables some to mature to adults, or merely to produce a few nymphs, albeit they may not develop into a viable colony.

reservoir host:

(an epidemiological, anthropo-centric, term) a host which serves as a source of reinfestation or reinfection. A reservoir-host is often the pathogen's 'natural host' or 'main host' or 'primary host', and may show little-or-no ill-effect from that pathogen - especially where the infection or infestation is a zoonosis. 'Secondary', less-preferred hosts are important where eradication is attempted.

Beware - the terms primary host, secondary host and reserve host are used very differently regarding aphid hosts.


patterned with a network of lines.

See also: AphID.


sensory patches on the antennae of aphids, presumed to be (at least primarily) smell-receptors.
primary rhinaria:
are large & plate-like, on the terminal segment or segments.
secondary rhinaria:
are small, on any of segments 3 4 5 & 6 of Aphididae.


beak-like labium (or lower-lip) usually of 4 segments, supporting the stylets (modified mandibles and maxillae that form the salivary canal and food canal).

See also: Amateur Ent. Soc., AphID, Wikipedia.
Aphids on World Plants

See also: Wikipedia.


hardened plate, sometimes also thickened and darkened.


a small hardened plate (sclerite) encircling the base of a single hair.

See also: AphID.


hardened, sometimes also thickened and darkened.


the posterior (third) dorsal sclerite of each thoracic segment of an insect (usually the mesonotum). In Heteroptera and some Coleoptera the scutellum is a small triangular plate between the forewing bases and behind the pronotum.

See also: Wikipedia.

secondary host:

a plant species (usually herbaceous) upon which a host alternating aphid species reproduces entirely asexually, usually during the warmer season - but sometimes all year round. Many aphid species spend the warmer season on a 'secondary' host plant, and move to a 'primary' usually-woody host plant for the cooler season.

Note, in parasitology, a secondary host harbors a parasite for only a short period during its develpoment. See Wikipedia.

secondary rhinaria:

small sensory patches on the third, fourth and fifth antennal segment of aphids, presumed to be (at least primarily) smell-receptors.


a simple sensory receptor, typically hair-shaped or rod-shaped. A modified cell, or small group of cells, of the cuticle or epidermis.


bristle or stiff hair, or a structure resembling such.

See also: AphID, Wikipedia.


sexual forms. Males and oviparae (females that lay eggs, not live young).

sexuparae (=gynoparae):

parthenogenetic females that bear the sexual generation. In other words: females whose offspring develop to sexual forms. In host alternating species these are the returning migrant alates.

siphunculi (= cornicles, US):

a pair of (dorsal, posterior) abdominal tubes that secrete a defensive fluid. Most aphid species (but no non-aphids) have siphunculi.

See also: Amateur Ent. Soc., AphID, Wikipedia.


wingless, parthenogenetic female adelgids that have a period of diapause in the first instar.


chemosensory / olfactory setae (simple hairs) with immovable bases and banded patterns.


flattened rounded and broad at top, attenuated at base. Like a spatula, oar-blade, spade or spoon.

spinal tubercles:

rounded bumps that protrude from near the midline of the insect's dorsum.


a lateral series of pores that allow air to enter the tracheal tubes, which deliver oxygen to the tissues.

See also: Amateur Ent. Soc., Wikipedia.

spring migrant:

the winged-form which moves from the primary (=winter) host to the secondary (=summer) host in spring.


ventral sclerites of an abdominal segment.

See also: Wikipedia.


the psyllids, scale insects, aphids, adelgids and Phylloxerids. Originally within the suborder Homoptera, it is now a suborder, and considered the most primitive Hemiptera, but recent evidence (see Li, Hu; et al., 2017.) suggests Hemiptera and Sternorrhyncha are sister groups within the superorder Exopterygota (=Hemipterodea).

See also: Wikipedia.


a stigma is the pore, or hole, at the center of a spiracle.

stigmatic plates:

a plate found adjacent to or surrounding a spiracle. (Stigma:from Ancient Greek - meaning a mark, spot or brand.)


a pair of threadlike mouthparts extruded from the rostrum which form a tube for piercing, then conveying liquid nutrients into the aphid.

See also: Wikipedia.

subgenital plate (=genital plate):

a sternite common to all adult female aphid morphs; present in reduced size in late instar immatures. Behind its posterior margin is the genital orifice, gonapophyses, anal plate, then anus.

supracaudal process:

a protuberance above the cauda, which can make the aphid appear to have 2 tails.

syrphids (hover-flies, flower flies, sun flies):

Diptera of the family Syrphidae that mimic bees/wasps. The larvae of some species are aphid predators. Note, syrphids whose larvae are known as 'rat-tailed maggots', and live in sewage, do NOT feed upon aphids.

See also: Wikipedia.

systemic insecticide:

an insecticide that spreads through the entire plant, as opposed to one which is only active on the part of the plant to which it is applied.

See also: Wikipedia.


the segments that would correspond to a 'foot' in humans.

See also: Amateur Ent. Soc., AphID, Wikipedia.


Recently moulted - before the newly-exposed cuticle has hardened and darkened. Tenerals are therefore soft and atypically pale, and winged tenerals have problems flying.

See also: Amateur Ent. Soc.


the dorsal plate covering a segment.

See also: Wikipedia.

terminal process:

the narrower part of the last antennal segment sometimes called the processus terminalis or unguis.

See also: AphID.


lower part of the leg, corresponding to the calf in humans.

See also: Amateur Ent. Soc., AphID, Wikipedia.


any outgrowths of the plant - including hairs, scales, or papillae.

See also: Wikipedia.

triommatidium (=triommatidion):

a group of three ocular facets, in most aphids on an ocular tubercle on the postero-lateral part of the compound eye. It is functionally distinct from the ocelli and compound eye, but is derived from compound eye facets in the embryo. Since compound eyes may not develop fully in early instars, triommatidla are also known as 'persistent larval eyes', or 'primary compound eyes'.

See also: AphID,


a braconid genus of aphid parasitoids, comprising 50 species worldwide - characterised by the first tergite having a pair of spiracular tubercles, and the terminal metasomal sternite having 2 posterior prongs. Trioxys have been used for biological control of aphid pest species. Trioxys pallidus was introduced to control the walnut aphid, Chromaphis juglandicola, in USA.


the second leg segment, counting from the body - lying between the coxa and the femur.

See also: Amateur Ent. Soc., AphID, Wikipedia.


bearing one brood of offspring a year.

See also: Wikipedia.


the apex of the head, usually bearing ocelli in insects.


females that give birth to live young. All viviparous aphids are parthenogenetic.

See also: Amateur Ent. Soc., AphID.


an environment or habitat that is extremely dry, lacking humidity and water.

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See also: Wikipedia Glossary of entomology terms.