abdomen: one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs

alate: winged

antenna (pl. antennae): pair of segmented, sensory structures (feelers) projecting from the heads of insects

anterior: situated near the front of the body; nearer to the head

apical: far from the base, the tip of a structure

appendage: any limb or organ that is attached to the insect's body by a joint

apterous: without wings

arista: a large bristle located on the apical antennal segment for dipteran species

axil: the upper hollow where a leaf or flower attaches to a stem


basal: at or near the base of a structure

bronzing: smooth, dark brown discoloration to plant tissues as a result of insect damage


calyx: whorl of residual flower parts that include the sepals, found at the stem end of a fruit

canopy: referring to the crown of a tree that includes the leaves, stems, and branches

caterpillar: common name for larval lepidopterans (butterflies and moths)

cauda: a v-shaped structure extending from the rear of the aphid abdomen

cercus (pl. cerci): segmented, paired appendages at the rear of the abdomen, usually triangular and short in grasshoppers

chewing mouthparts: mouthparts designed for biting and chewing; mandibles move from side to side with overlapping edges that cut like scissors as well as surfaces for grinding; characteristic of orthopterans

chlorosis: yellow or white spotting on leaves and fruit resulting from feeding by certain pests

chrysalis: another term for the pupa of a butterfly

cilia: slender hairs that outline the forewings and represent modified setae; a diagnostic characteristic of thrips (order Thysanoptera)

clavate: word used to describe antennae in which the last, terminal segments are wider towards the tip forming a club-like shape

clypeus: a sclerite on the head of the insect positioned below where the antennae attach and articulated with the labrum on the other side

cocoon: the protective covering around the pupa of some insects

compound eye: an eye comprised of many individual eye elements called ommatidia that each have a lens; the main visual organ in insects

concave: shaped or curved like the inner surface of a sphere

convex: shaped or curved like the outward surface of a sphere

cornicles: paired, triangular-shaped tubes projecting from the rear of an aphid abdomen; also referred to as siphunculi

costal fold: a fold along the leading edge of the lepidopteran forewing that contains scent scales used to attract members of the same species

coxa: basal segment of insect leg that is connected to the body by a joint

crawler: the mobile first instar of many scale species

cremaster: a hook or series of hooks at the terminal end of the abdomen in some lepidopterans, used to attach the butterfly or moth to the pupation site

crochet (pl. crochets): small, hook-like structures that extend in a circle from the prolegs found on larval lepidopterans


diapause: temporary cessation of development caused by a physiological response to unfavorable conditions

distal: appendage or part farthest from the body

dorsal: the upper surface of an insect


eclosion: the emergence of an insect from an egg or pupa

elytron (pl. elytra): hardened or sclerotized pair of forewings in beetles

emergence: used to describe the completion pupation that culminates in the appearance of the adult form of an insect

ensiform: word used to describe antennae that are sword-like and broad at the base, but narrowing to the tip

epidermal cells: layer of plant cells immediately beneath the waxy covering on the surface (the cuticle)

exudate: fluid released naturally from the body openings of insects or from wounds in insects or plant tissues

eyespots: markings on an insect, usually the wing, that resemble a large eye


femur: from the base of the insect body, the femur is the third segment of the insect leg, situated between the trochanter and tibia

filament: long thread-like structures extending from the body of insects, typically from the abdominal segments (e.g., mealybugs)

filiform: type of antenna that is uniformly thin and threadlike throughout its length

flagellum (pl. flagella): the outermost part of the antenna, beyond the scape and pedicel, usually divided into many subsegments (flagellomeres)

flush: period of rapid growth in the terminal shoots of citrus trees that may be associated with flowering or may be vegetative

foliar: relating to foliage (leaves)

forewing: the anterior (closest to the head) pair of wings in insects

frass: pellets of very dry excreta produced by some insects

furcula: forked projection from the posterior edge of the abdomen and overlying the supra-anal plate of male grasshoppers


gall: a distorted area of stem or leaf tissue arising from the plant's response to attack by certain pests and pathogens

gaster: the bulbous part of the ant abdomen located behind the waist (petiole)

generation: the time it takes for an insect to develop from egg to adult

geniculate: adjective used to describe antennae in which there is an abrupt bend or 'elbow' along the length of the antennae

genitalia: external reproductive structures

girdling: removal of the bark, phloem, and cambium tissues around the entire circumference of the effected plant part (branch, root, or trunk) that results in the death of the wood beyond that point; characteristic damage inflicted by specific insects like beetle larvae

gravid: female that is bearing eggs

gregarious: exhibiting the behavior of moving or feeding in a group of individuals of the same species; early instars of many insects feed in groups

grub: an immature stage in the life cycle of insects; larvae of beetles are often referred to as grubs


haltere (pl. halteres): the club-shaped, modified hindwing of flies (order Diptera) that plays a role in moderating balance and stabilization in flight

head: one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts

hemelytra: the forewings typical of many hemipterans; the base of the wing is leathery and the tip of the wing is membranous

hemimetabolous: simple metamorphosis that consists of a series of molts and lacks a true pupal stage

hindwing: the posterior or rear pair of wings in insects

holometabolous: complete metamorphosis that includes egg, larval, pupal, and adult phases

honeydew: the sugar-rich waste product excreted by aphids, mealybugs, and scales insects as a result of feeding on the phloem of plants

host plant: the plant the provides sustenance for an insect

host range: the range of species that a particular organism can feed on to achieve successful growth and reproduction

hyaline: transparent and glassy


imago: the adult stage of an insect

immatures: term used to describe the sub-adult stages of insects that do not undergo complete metamorphosis; see also nymph

instar: immature stages (larva or nymph) of insects in between molts

integument: the outer covering of an insect's body

invasive: term used to describe species that are not native and have the ability to adversely effect habitats they invade either ecologically or economically


larva (pl. larvae): the immature or juvenile stage of certain groups of insects that undergo complete metamorphosis that includes a pupal stage; these juveniles often look very different from the adult form and are missing structures (e.g., wings) that are found in the adult

lateral: with an orientation pertaining to the side


maculate: spotted

maggot: an immature stage in the life cycle of insects; fly larvae are often referred to as maggots

mandibles: the jaws of insects with chewing mouthparts

medial: situated in or closest to the middle

membranous: with the same character as a membrane, typically used to refer to structures like wings that are clear and translucent like a membrane

mesothorax: the second or middle segment of the thorax

metathorax: the third and last segment of the thorax

mobile: able to move

molt: process of shedding the external skeleton during periods of growth; occurs between successive instars of a larva or nymph

moniliform: type of antennae where successive round segments make the antenna as a whole appear like a string of beads

motile: able to move


necrotic: the damage caused by cell death (necrosis) in plants or other organisms, often a result of insect feeding on plants, and displayed as brown or black coloration of tissues

nymph: the immature or juvenile stages of insects that do not undergo complete metamorphosis; look similar to the adult and develop to the adult stage through a series of incremental changes that does not include a pupal stage


ocellus (pl. ocelli): the simple eye of an insect that consists of a single, bead-like lens, typically located at the top of the head in insects that undergo complete metamorphosis; absent in lepidopterans and reduced in many other species

oviposition: the act of depositing eggs

ovipositor: a tubular structure extending from the abdomen of female insects that is used to lay eggs

ovisac: structure attached to the body that contains eggs; produced by many scale insects


parthenogenesis: a form of asexual reproduction in which a female produces eggs without fertilization by a male

pedicel: from the base, the second segment of the antenna, located between the scape and the flagellum

petiole: the first segment behind the metathorax that connects the thorax to the gaster of an ant; often referred to as a "waist" because the segments are slender and appear as a constriction between the two body sections

pheromone: chemical substance secreted by an animal that influences the behavior of another animal

piercing-sucking mouthparts: labium encloses the mandibles and maxillae, which are modified into stylets for piercing and sucking; characteristic of hempiterans

posterior: orientation pertaining to the rear of the body

postpetiole: the second segment of the "waist" which, if present, is located directly behind the petiole; only present in certain familes of ants

pre-pupa: the non-feeding last instar larva of insects that undergo complete metamorphosis

probing-sucking mouthparts: mouthparts are modified into a long, slender proboscis specialized to probe flowers and suck out nectar; characteristic of butteflies and moths

proleg: unsegmented, fleshy, foot-like structure extending from the abdomen of many larval lepidopterans that aids in locomotion, but are not true legs like those found extending from the thorax

pronotum: the dorsal surface of the first thoracic segment

propupa: a non-feeding stage in the development of thrips and male scales immediately before formation of the pupa

prothorax: the first segment of the thorax

pterostigma: a thickened cell on the outer margin of the wing in some insects

pulp: the soft, moist, internal part of the citrus fruit, beneath the rind and albedo layers

pupa (pl. pupae): the non-feeding, immobile developmental stage of holometabolous insects during which the larva develops into an adult that is very different in form

puparium: the rigid outer shell formed from the discarded larval skin that protects the pupa of certain flies


rasping-sucking mouthparts: mouthparts that are modified to rasp or scrape the surface of plant tissues and suck up the fluid that flows from damage tissues; characteristic of thrips

ring scar (or halo mark): a circular blemish on fruit caused by pest damage to the rind around the calyx during early fruit development


scape: basal segment of the antenna

scent gland: a gland which secretes an offensive, odorous fume for protection

sedentary: not mobile

sessile: not mobile

seta (pl. setae): stiff hairs or bristles

setaceous: word used to describe antennae in which the flagellum is reduced and tapers gradually from the base to the tip

silk: a natural fiber produced by some insects that can be utilized to construct shelters, leave a trail, build a cocoon, etc.

siphunculi: paired, triangular-shaped tubes projecting from the rear of an aphid abdomen; also referred to as cornicles

solitary: insects that feed or move about individually, not in groups

spine: a thorn-like outgrowth of the integument (exoskeleton) that is not separated from it by a joint

sponging mouthparts: mouthparts are modified for sponging up liquid food by capillary action; saliva containing digestive enzymes may be used to liquify solid food; characteristic of dipterans

spur: a spine-like process of the integument (exoskeleton) that is connected by a joint

stigma (pl. stigmata): prominent, darkened cells on the forewings of some male lepidopterans that produce pheromones to attract females


tarsus (pl. tarsi): the last, distal segment of the insect leg, composed of sections called tarsomeres, usually ending in a claw

thorax: one of the three main body segments in an insect, located between the head and abdomen, where the wings and legs of the insect attach

tibia: from the base of the insect body, the tibia is the fourth segment of the insect leg, situated between the femur and the tarsus

trochanter: from the base of the insect body, the second segment of the insect leg, situated between the coxa and the femur

tubercle: a small raised bump or rounded protuberance, typically, describing a raised bump on a caterpillar that bears a spine orthe rounded bumps that the antennae of aphids extend from

tympanum (pl. tympana): a vibrating membrane that serves as an auditory organ in some insects


ventral: bottom surface of the body


wing pads: undeveloped or incomplete wing structures that are found on the immature individuals of insects that do not undergo complete metamorphosis, e.g., stink bugs, leaf-footed bugs, grasshoppers