Glossary Of Terms

Glossary of Terms

The definitions given below are specific to this Web Site; in other works, they may have additional meanings. Sources used in compiling these definitions include "The Torre-Bueno Glossary of Entomology" (1989) and "The Random House College Dictionary" (1988). Where appropriate, the plural of a word is given in parentheses, usually with the notation of "pl."


Select the first letter of the word from the list above to jump to appropriate section of the glossary.

- A -

        The posterior or hindmost body region.

Abdominal festoons
        In ticks (Acari), the rectangular areas divided by grooves along the posterior abdominal margin.

Accessory vein
An extra branch of a longitudinal vein; in Hymenoptera, the most posterior vein in the anal area of the front wing.

    Inflammation of 1 or more lymph nodes.

The fully grown, sexually mature arthropod.

        To go into a quiescence or resting period as a result of continued high temperature or dry conditions.

Winged form; possessing wings.

Allergic reaction
        A hypersensitivity to foreign proteins, developed only after an initial exposure.

        Having no metamorphosis.

        In beetle (Coleoplera) larvae, the paired ventral proleglike protuberances on abdominal segments of some species.

Anal groove
        In ticks (Acari), a groove which either is in front of or behind the anal opening.

Anal lobe
        A lobe on the posterior part or rear margin of the wing.

Anal plate/shield
In mites (Acari), the ventral rear/posterior scierotized/hardened plate/shield surrounding the anal opening.

Anaphylactic shock
        A collapse of circulatory function resulting from a generalized total body allergic reaction caused mostly by insect stings, spider bites, ingested foods, and drugs; a life-threatening condition.

        Appears to consist of or to be subdivided into ringlike segments; ringed; surrounded by ring of a different color.

Antenna (pl. antennae)
        The paired, segmented feelerlike sensory organs located on the head above the mouthparts.

        Front, in front, before.

Anticostal suture
        In insect larvae, the transverse line/groove near the front margin of the segment on the dorsal/top surface.

        Anterior portion of heart (dorsal vessel), lacking lateral openings or ostia.

        In snails (Geophila), the shell opening.

Aperature lip
        In snails (Geophila), the edge of the shell opening.

        A member of the insect order Homoptera, family Aphididae, characterized by being soft-bodied and nearly always with a pair of cornices (tubular structures) near the posterior/rear end of the abdomen; commonly called plantlice.

Arolium (pl. arolia)
        In insects, the terminal pad between or pads under each claw of the pretarsus.

        Any segmented invertebrate of the phylum Arthropoda, having jointed legs.

        In beetle (Colsoptera) larvae, the condition where the surface is covered with short toothlike structures.

        Not symmetrical (evenly developed on both sides).

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- B -

     A transverse marking different in color from the background color, may completely ring a structure such as the tibia.

Basal cell
        In adult flies (Diptera), the elongate cell behind the radial or medial veins located in the basal half of the wing.

Basement membrane
        The thin, acellular, innermost layer of the exoskeleton.

Basis capituli
        In ticks (Acari), the base for the mouthparts.

        Any notable prolongation of the front of the head; a snout.

        Of two (2) different colors.

Bilateral symmetry
        The left and right sides are essentially similar.

        In spiders (Araneae), the internal breathing structures located inside the abdominal venter with slitlike openings to the outside.

        A stiff, usually short and blunt, hairlike projection.

Broadleaf tree
        A tree which in general has wide/broad leaves (vs. needlelike) and is usually deciduous, shedding its leaves seasonally and being leafless for part of the year; hardwoods.

        All individuals that hatch about the same time from eggs laid by one series of parents; in social insects, the immature members of the colony collectively, including eggs, nymphs, larvae, and pupae; in birds (Aves), the number of young produced or hatched at one time.

        The process in which reproductives or potential reproductives, workers, and certain immature leave the parent or major colony to start a new colony.

Bursa copulatrix
        An internal female organ functioning during copulation; in mites (Acari), the distal and of the seminal receptacle.

        In fly (Diptera) larvae, a usually round structure/scar on the posterior spiracle representing the spiracle of the previous instar.

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- C -

        Anything hidden or stored.

        Containing calcium.

Calypter (pl. calypteres)
        In adult flies (Diptera), one of 2 basal lobes located at the base of the wing along the rear margin.

        In trees, the layer of living cells located between the bark to the outside and the sapwood to the inside.

        In ticks (Acari), the mouthparts and their base.

        In Crustacea, the hard top/dorsum of the cephalothroax (fused head and thorax); in scorpions (Arachnida), the hard dorsal covering consisting of fused dorsal scierites/plates of the cephalothorax (fused head and thorax).

        An elevated ridge or keel.

        Predacious, eating/feeding on animal fluids and/or tissue.

        In termites (isoptera), the nest building material composed of semidigested wood and soil cemented together with saliva and feces.

        A milk protein used in cheese, paint, etc.

        Kinds of mature individuals among social insects which share similar body form and job description.

Caudal filaments
Threadlike processes at the posterior/rear end of the abdomen.

        Centers for Disease Control, headquartered in Atlanta, GA.

Cell (of wings)
        The space between the wing veins.

        A polysaccharide consisting of repeated glucose units, which is a major component of plant cell walls.

Centimeter (cm)
        0.01 meter; 0.394 inch; about 2.5 cm = 1 inch.

        Anterior body region composed of the fused head and thorax.

Cercus (pl. cerci)
        One of a pair of dorsal appendages at the posterior end of the abdomen.

        In mites (Acari), mandiblelike chelicerae.

Chelicera (pl. chelicerae)
        One of the anterior pair of appendages, usually fanglike, in arachnids.

        Stripes meeting at an angle medially; "army sergeant stripes."

        A major polysaccharide component of arthropod cuticle, secreted by the epidermis.

        A member of the insect order Homoptera, family Cicadidae, characterized as being large (mostly 1-2"/25-50 mm), wings membranous and held rooflike over the body at rest, antennae short and bristielike, 3 oceiii, tarsi 3-segmented, and males usually with sound-producing organs at the base of the abdomen on the ventral side.

        In beetles (Coleoptera), the scarlike structure located at the apex of the lst antennal segment (scape) in some species.

        One of a pair of clasping structures located at the end of the abdomen functioning to hold the female during copulation

        Thickened or widened towards the base, or the apex (=clubbed).

Claw tuft
        A bunch/tuft of hairs (setae) at the tip of the tarsus, sometimes padlike.

Closable chimney cap
        A chimney cap which is spring-loaded with a cable running through the flue pipe and a lock-catch located in the fireplace.

Closed cell
        The membranous space of a wing being enclosed or bounded by veins on all sides.

        In birds (Aves), the number of eggs produced or incubated at one time.

        On the insect face, a scierits (hardened body wall plate) located between the front (central front area) and the labrum (upper lip).

        A member of the insect order Homoptera, superfamily Coccoidea, characterized by males midgelike with I pair of wings, tarsi 1 -segmented with I claw, and without a beak, and females wingless and often legless, usually with a waxy or scalelike covering; scale insects and mealybugs.

        The covering of the pupa, composed partly or wholly of silk, constructed by larvae.

        In springtails (Collembola), a ventral tube borne on the first abdominal segment which is thought to function in water uptake.

        In rodents, those which live in close association with humans and whose needs are supplied by humans.

Complete metamorphosis
        In insects, development where the immature stages consist of an egg followed by a series of larvae and then a pupal stage before the adult.

Compound eye
        An eye composed of many separate visual elements, each of which is indicated externally by a facet.

        Having a common center, as circles.

        Evergreen tree g., pine, spruce, fir, etc.

        Inflammation of the mucous membrane that lines the inner surface of the eyelids.

        Narrowed, pinched-in.


        To be oriented as if coming together at a point; inclined towards each other.

        The dried oil-bearing kernel and meat of coconut.

        In aphids (Homoptera: Aphididae), the tubular structure on each side of the 5th or 6th abdominal tergites (dorsal) through which various alarm pheromones are released.

Costal vein broken
        In insect wings, the heavy front marginal vein if it has distinctive weak spots usually indicated by a marginal notch.

Coxa (pl. coxae)
        The basal or 1 st leg segment, connected to the body wall.

Coxal plate
        The hardened plate to which the coxa is attached.

Creaping welts
        In insect larvae, the typically swollen and roughened areas/bands usually located on the ventral surface of segments which assist in locomotion.

        Active at dusk/sunset.

        In moth and butterfly larvae (Lepidoptera), the small hardened hooklike structures located on the end of the abdominal prolegs.

        In insects, the dilated portion of the alimentary canal behind the esophagus, which serves to receive and hold food.

        Transverse veins linking the major longitudinal wing veins.

        The thin, acellular, external layer of the exoskeleton, composed of 3 layers.

        A toxin which affects the cells in the immediate area of injection or introduction.

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- D -

        In the Gryllotalpidae (Orthoptera), the greatly enlarged terminal teeth of thebroad, compressed front tibia.

Deciduous tree
        A tree which looses/sheds its leaves seasonally, being without leaves for part of the year; most broadleaf or hardwood trees.

        Inflammation of the skin.

        To dry.

        Feeds on decaying organic matter.

        In mites (Acari), the normal 3rd instar (Ist=larva, 2nd=protonymph).

        In chiggers (Acari), the 2nd stage of development (Ist=egg, 3rd=larva, 4th=nymphochrysalis, 5th=nymph, 6th=imagochrysalis, and 7th=adult).

Developmental time
        The period from egg fertilization to emergence of the adult; egg to adult.

        Microscopic, single-cell algae having siliceous cell walls.

        Movement in a transverse plane towards each other.

        In adult flies (Diptera), having the eyes markedly separated medially.

        Occurring in 2 distinct forms.

        Active during the day; active at sunrise and sunset.

        Pertaining to the back or upper surface; top or uppermost.

Dorsoventrally flattened
        Flattened top to bottom, like a pancake.

        The male bee in Hymenoptera which develops from an unfertilized egg.

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- E -

        In bats (Chiroptera), the method of locating objects by determining thetime for an echo to return and the direction from which it returns via the use of a series of supersonic sounds (about 30-60 squeaks/sec with a pitch of 30-100,000 cycles).

        An external parasite.

        Abruptly bent in an obtuse angle (between 90-180’).


Elytral interval
        In adult beetles (Coleoptera), the longitudinal space between the striae (depressed/impressed rows of punctures).

Elytron (pl. elytra)
        The leathery or hard front wing of beetles (Coleoptera).

        Notched at the margin,

Empodium (pl. empodia)
        In mites (Acari), the enlarged pretarsal/terminal structure of the tarsi, may be padlike, etc.

        The chitinous internal layer of the cuticle.

        In arthropods, to fill to excess with blood.

        The study of insects, that branch of zoology dealing with insects.

        The thin acellular layer located on top of the exocuticle.

        The middle, cellular layer of the exoskeleton.

Epipharyngeal papillae
        In beetle (Coleoptera) larvae, tiny projections in a cuplike structure on the inner surface of the upper lip (labrum) along its midline near its outer edge.

        Hard crust or scab.

        A tree or other plant which does not shed its leaves until they are replaced by new leaves, always with green leaves; leaves narrow and often needlelike.

        Moderate to fine wood shavings once commonly used as packing material to protect the inner contents from damage due to blows to the box/container.

        The hard (scierotized), chitinous, outside layer of the cuticle.

      A skeleton or supporting structure, on the outside of the body.

External feeder
        The larva feeds from the outside of the kernel inward (stored product pests).

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- F -

        The external surface of a single compound eye unit or ommatidium.

Fang furrow retromargin
        In spiders (Araneae), the side opposing the fang.

        In spiders (Araneae), the chelicerae/jaws modified for injecting venom.

        Feverishness; pertaining to or marked by fever.

Fecal pellet
        In termites (Isoptera), the desiccated faces/excrement in the form of hexagonal configurations; firm/hard excrement or waste expelled from the anus.

        The average number of eggs laid by an arthropod.

Femur (pl. femora)
        The 3rd leg segment, located between the trochanter and the tibia.

        In ticks (Acari), the rectangular areas divided by grooves along the posterior margin of the abdomen.

Fiber saturation point
        The maximum amount of moisture vapor that wood can absorb from a saturated atmosphere.

        A long slender process of equal diameter throughout.

Fledged young
        In birds (Aves), when the nestling or young bird is able to fly.

        In termites (Isoptera), the porelike opening on the frontal region of the head through which secretions of the frontal gland are ejected/squirted.

        In snails and slugs (Geophila), the ventral or bottom surface usually containing openings to the mucus glands; in vertebrates, the terminal part of the leg, below the ankle joint, on which the body stands and moves.

Forensic entomology
        Any legal or courtroom activity involving insects, including the use of insects to determine the postmortem interval in criminal cases (medico-legal entomology).

        Solid excrement of larval insects; plant fragments made by wood-boring insects which are usually mixed with excrement.

Frontal bristles
        In adult flies (Diptera), the bristles located on the face to the outside of the swollen median vertical area and antennae bases, but before or to the inside of the eyes.

        A method of pest control in which the infested commodity/object/structure is encased so as to be almost air-tight, then a lethal fumigant (liquid/gas/solid) is released from within or introduced from the outside and held until the pests are dead, then the seal/encasement is broken so that aeration can begin, after aeration the commodity/object/structure is verified by using an appropriate detection device as containing a concentration of fumigant below the EPA acceptable level, and then the commodity/object/structure can be released back into the possession of the owner or their agent; in some cases, fumigation can be accomplished by using modified atmospheres which are lethal to the pests instead of traditional fumigants; or a combination of the two techniques can be used.

Functional worker
        In termites (Isoptera), workers who are either male or female and not sterile.

Fungus (pl. fungi)
        A plant which does not contain chlorophyll-e.g. molds, mushrooms, mildews, etc.

        In insect antennae, the segments between the lst segment/scape and the club.

        A forked process; in springtails (Collembola), the forked spring or leaping appendage borne on the 4th or 5th abdominal segment.

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- G -

Ganglion (pl. ganglia)
        A nerve center composed of a cell mass and fibers.

        The swollen part of the abdomen behind the waist or pedicel in Hymenoptera.

Gastric caecum (pl. caeca)
        A midgut structure which is saclike or tubelike and open atonly one end.

Genal comb
        In adult fleas (Siphonaptera), a row of strong spines located anteroventrally on the gena (cheek).

        From any given stage in the life cycle to the same stage in the immediate offspring.

        Structures associated with the genital opening and used during copulation.

Genitoventral plate/shield
        In mites (Acari), the sclarotized/hardened ventral plate located between the anterior sternal shield and posterior anal plate/shield containing the genital opening; the middle plate/shield.

Gestation period
        The time from conception, through development, to delivery/birth.

        A respirator organ in aquatic immature stages via which dissolved oxygen is extracted from the water.

        Spherical or nearly so.

Glossa (pl. glossae)
        The tongue; in adult Hymenoptera, the median lobe at the apex of the prementum (median portion of labium/lower lip).

Gradual metamorphosis
        In insects, development where the immature stages are the egg followed by a series of nymphs which are very similar in appearance to and habits of the adult stage; with no pupal stage.

        Surface texture as if covered with or made up of very small grains or granules.

Gravid female
        Heavy with fully-developed eggs.

Green logs
        Freshly cut logs which have not had their wood moisture content reduced to below 20% (=seasoned).

        Commonly found in groups or aggregations.

Gynecoid worker
        In Hymenoptera, a worker ant which can and does lay eggs and can function as a substitute queen.

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- H -

Haemolymph (also hemolymph)
        In insects, the blood which consists of fluid plasma containing suspended hemocytes (nucleated cells).

        A slender flexible filament of equal diameter throughout, commonly used for seta/setae; by definition, found only on mammals.

Haller’s organ
        In ticks (Acari), a sensory organ located on the first pair of legs, on the top of each tarsus.

Haltere (pl. halteres)
        In adult flies (Diptera), the knoblike modified hind wing which is a sensory organ and helps maintain stability in flight.

        The wood of broadleaf or deciduous trees, such as oak, walnut, etc.

        Spear-headed hairs (setae) often found in tufts arising from the tergites, especially the posterior segments of dermestid larvae (Coleoptera: Dermestidae).

        The anterior or front body region which bears the eyes, mouthparts, and antennae.

        See haemolymph.

        A body cavity filled with blood.

HEPA filter
        High efficiency particulate air filter, removes particles down to 0.3 microns in size.

Herbarium (pl. herbaria)
        A systematically arranged collection of dried plants, or a room(s) in which such a collection is kept.

        Feeds on plants.

        Individual containing both ovaries and testes.

        Period of inactivity during seasonal low temperatures.

        In adult flies (Diptera), having the eyes touch each other medially.

Honey dew
        The watery fluid containing which is excreted from the anus of aphids, scale insect, treehoppers, and most planthoppers (all in order Homoptera).

Humerus (pl. humeri)
        In adult beetles (Colooptera), the basal exterior (lateral) angle of the elytra; the shoulders.

Hypha (pl. hyphae)
        A threadlike strand of fungus.

Hypopdial stage
        The hypopus.

        A median mouthpart structure located just in front of the labium; a tonguelike structure.

        In adult flies (Diptera), the plate just above the middle coxa on the side of the thorax.

Hypopus (pl. hypopi)
        A nymphal stage in the development of certain mites (Acari) which has developed suckers or claspers for grasping insects, effecting dispesal.

In ticks (Acari), a dartlike structure arising fom the median ventral surface of the basis capituli.

        In mites (Acari), the clorsolateral area between the 2nd and 3rd pair of legs.

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- I -

        In mites (Acari), the body.

        Insect light trap which uses black (ultraviolet) light to attract insects and either electrocutes them on an electrical grid or captures them on a replaceable sticky surface.

        The adult stage.

        In chiggers (Acari), the 6th stage of development (Isl=egg, 2nd=Deutovum, 3rd=larva, 4th=nymphochrysalis, 5th=nymph, and 7th=adult).

        A life stage proceeding the adult stage; not sexually mature.

Impressed areas
        Areas of the surface which are lower than the surrounding or overall surface height.

Incomplete metamorphosis
        In insects, development where the stages are the egg followed by a series of naiads which are aquatic and have gills, the naiads differing greatly in appearance from the adult stage; with no pupal stage.

Insect growth regulator (IGR)
        A substance which affects the insect’s developmental cycle and disrupts its tile cycle.

        The stage between molts.

Interfemoral membrane
        In bats (Chiroptera), the membrane between the hind leg and tail.

Intermediate host
        The host in which the asexual stages of a parasite are passed.

Internal feeder
        The larva feeds entirely within the grain kernel and usually requires a whole kernel for development (stored product pests).

        Displaying a shifting/change of lustrous colors (shines by reflection) when the viewing angle is changed.

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- J -

Jugal lobe
        In adult Hyrnenoptera, the lobe on the hind margin of posterior/rear wing near the body.

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- K -

        An elevated ridge; in cockroach oothecae (Blattodea) , the raised dorsal ridge.

        An inert animal protein found in hair, feathers, horns, hoofs, etc., akin to chitin of insects.

Kiln-dried lumber
        Lumber which has been artificially warmed or heated to reduce its moisture content and to kill any insect infestation.

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- L -

        In some adult flies (Diptera), the fleshy paired oral lobes or pads at the terminal end of the proboscis,

Labial palp (pl. palpi or palps)
        The 1-4-segmented appendage of the insect labium (lower lip).

        The lower lip, located below the rnaxillae; hindmost mouthpart structure.

        The upper lip, located in front of the mandibles and below the elypeus. Lanceolate Spear-shaped; oblong and tapering to one end.

Larva (pl. larvae)
        An immature stage of those insects with complete metamorphosis; the developmental stage between egg and pupa; in termites (Isoptera), the young instars proceeding the worker or nymph (with wing pads) stages; in thrips (Thysanaptera), the Ist 2 instars; in mites and ticks (Acari), the lst instar.

        Shaped like or resembling a larva.

        Toward the side, away from the midline.

Laterally flattened
        Flattened side to side.

        A member of the insect order Homoptera, family Cicadellidae, characterized by having the mouthparts in a beak arising from the back of the head, antenna short and bristielike, 4 membranous or slightly thickened wings with front wings longer, middle coxae short and touching each other, hind tibia with I or more rows of small spines, and jumping insects, generally less than 112" (12 mm).

Life cycle
        The development of an insect from egg stage to egg stage.

Life history
        A detailed record of a life cycle (egg to egg).

        An organic material that along with cellulose, forms the primary part of woody plant tissue; adds strength.

        A number of young born at approximately the same lime.

        Wood which is 1 "/24 mm or less in thickness.

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- M -

        Fly (Diptera) larvae which are legless and lack a distinct head (represented by 2 hooks), tapers from a blunt caudal/posterior end towards a pointed "head" end.

Major worker
        In termites (isoptera) and ants (Hymenoptera: Formicidae), a member of the worker subcaste of largest size.

Malipighian tubules
        Blind excretory tubes that arise near the anterior end of the midgut and extend into the body cavity; the insect’s urinary system.

        In ticks (Acari), the elevations of various forms found on the integument in Ornithodoros spp.

        A jaw.

        In slugs (Geophila), the raised portion of the body’s dorsum.

Manufactured product
        Wood which has been worked or processed such as millwork, flooring, and furniture.

        Of or pertaining to the edge.

        The ventral pouch in certain lsopoda and Amphipoda used for carrying eggs and young; brood pouch.

Maxilia (pl. maxillae)
        One of the paired mouthparts located just behind the mandibles, often jawlike and with a palp (segmented feelerlike structure).

        A member of the insect order Homoptera, families Pseudococcidas and Ericoccidae, characterized by being elongate-oval with well developed legs, tarsi 1- segmented with 1 claw, and usually covered with a waxy secretion.

Media worker
        In polymorphic ants (Hymenoptera: Formicidae) with 3 worker subcastes, a member of the worker subcaste of intermediate size.

Median caudal filament
        A threadlike process at the posterior end of the abdomen positioned in the middle.

Median frontal stripe
        In adult flies (Diptera), a stripe in the middle of the front/face of the head.

        Like cellophane; a thin, flexible, usually transparent, film of tissue.

Mesonotal suture
        In adult flies (Diptera), the impressed line running across the top of the middle thoracic segment (mesothorax) that subdivides the mesonotum; the transverse suture.

        The dorsal/top hardened plate of the middle thoracic segment (mesothorax).

        The lateral/side hardened plate of the middle thoracic segment (mesothorax).

        The second or middle segment of the thorax, bearing the middle pair of legs and front wings if present.

        Having the appearance of metal.

        The series of changes an insect goes through in its growth from egg to adult stage.

Metapodosomal venter
        In mites (Acari), the ventral area between the 3rd and 4th pair of legs.

Metasternal plate
        In insects, the hardened ventral plate of the middle throacic segment (mesothroax) located between the legs.

        The third or hindmost segment of the thorax, bearing the third pair of legs and the hind wings if present.

        (m) 39.37 inches; the standard of length in the metric system of measurement.

        Enclosed in a thin polymer skin, usually spherical.

        (mm) 1/1000 meter; 0.3937 inch; about 25 mm = 1 inch.

        A species which closely resembles another species of a different group for a survival advantage.

Minor worker
        In termites (Isoptera) and ants (Hymenoptera: Formicidae), a member of the worker subcaste of smallest size.

        The periodic formation of a new exoskeleton, followed by the shedding of the old skin.

        Composed of a series of beadlike segments; beaded like a necklace.

        Of or having one form.

        The study of form and structure.

        In birds (Aves), a tuft of feathers off the bill base often differing in color from the surrounding area.

Mycelial fan
        Flat masses of fungal hyphae.

        One who studies fungi.

        Any disease that results from the infestation of tissues or cavities by fly (Diptera) larvae.

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- N -

        The aquatic nymph of insects with simple or incomplete metamorphosis.

        In birds (Aves), the back side of the neck.

Nasutiform soldier
        In termites (isoptera), a soldier with the head prolonged into a snoutlike structure used to eject/squirt a defensive secretion.

        Decay; death of tissue.

Necrotic lesions
        A wound with dying tissue.

        A toxin that affects the functioning of the nervous system.

        The egg of a sucking louse (Anoplura) when attached to a hair.

        Active at night.

        A segment of the pedicel or of ant’s waist (Formicidae) or of other Hymenoptera.

Notopleural bristle(s)
        In adult flies (Diptera), bristles borne by the sunken lateral area to the outside of the mesonotal/transverse suture (=notopleura).

Notum (pl. nota)
        The dorsal or top surface plate of a thoracic segment.

Nuptia instar
        In amphipods/scuds (Amphipoda), the 8th instar which includes the first mating (adult begins with 9th instar).

        The immature stage of insects having incomplete (= simple) metamorphosis; in Acari, the immature stage(s) having 8 legs.

        In chiggers (Acari), the 4th stage of development (lst=egg, 2nd=Deutovum, 3rd=larva, 5th=nymph, 6th=imagochrysalis, and 7th=adult).

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- O -

Occipital carina
        In adult Hymenoptera, the carina/ridge delimiting the back of the head (occiput) from the top of the head (vertex).

Ocellus (pl. oceill)
        A simple eye, consisting of a single lens.

Ocular bristle
        In adult fleas (Siphonaptera), the bristle associated with the compound eye and usually inserted either in front of or below the eye.

Oesophagus (esophagus)
        That part of the alimentary canal between the mouth and the crop.

Ommatidium (pl. ommatidia)
        An individual compound eye unit or visual section.

Ootheca (pl. oothecae)
        Egg capsule; in cockroaches (Blattodea), two parallel rows of eggs enclosed in a capsule.

Open cell
        The membranous space between the wing veins continuous with or reaching the wing margin.

        In snails (Geophila), the closing plate of the shell.

        Closest to or opposite.

Oral vibrissae
        In adult flies (Diptera), the 2 long bristles, one located to each side of the face just above the mouthparts on the head.

Ostium (pl. ostia)
        Lateral openings of the heart (dorsal vessel), located in the posterior portion.

        The structure by which the eggs are deposited, may be external or withdrawn into the body.

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Palp (= palpus, pl. palpi)
        A feelerlike structure located on a maxilla or on the labium.

Papilla (pl. palpillae)
        Tiny fingerlike projections.

        In adult flies (Diptera), the head area between the lower 1/3 of the compound eye and the vertical front ridge (goes around the antennae bases).

        In adult flies (Diptera), the sides of the front of the head next to the compound eyes; the parts of the face between the facial ridges and the eyes.

        Living as a parasite, an organism that lives on or in another (the host) from which it obtains food, shelter, etc.

        An internal or external parasite.

        Up and down movement (vertical) in a plane almost parallel to the median plane of the body.

        In trees, simple blunt-ended storage cells.

Parent colony
        The main colony containing the queen(s), other castes, and immature including eggs.

        Egg development without fertilization.

Patella (pl. patellae)
        In Cholicerata (mites, ticks, spiders, etc.), the leg segment between the femur and the tibia.

        Any microorganism or its product which causes disease.

        Pest control operator; one engaged in pest control as a profession.

        Comblike; with even processes like the teeth of a comb.

        The waist of an ant (Formicidae) or of other Hymenoptera, composed of one segment (the petiole) or 2 segments (petiole plus postpetiole); the 2nd antennae segment of insects; in spiders (Araneae), the narrow waist/stalk connecting the cephalothorax and abdomen.

        The second pair of appendages of the cephalothorax in Arachnida.

Perimeter barrier treatment
        Application of a pesticide to the perimeter of a building, not to exceed 10 feet (3 m) outward or higher than 1-3 feet or to the bottom of any siding.

Peritremal tube
        In mites (Acari), a hardened/sclerotized tubelike structure extending forward, or sometimes rearward, near the lateral margin, from the stigmata (breathing pore).

        In fly larvae (Diptera), the margin of the spiracular plate; see Peritremal tube.

        The ability to absorb water; the relative ease with which moisture can penetrate under a pressure gradient.

        Oriented or being at a right angle (90’) to another surface.


        The first node or segment of the pedicel or waist of ants (Formicidae) and other Hymenoptera.

        A chemical usually secreted by a gland which is released outside the body and is used n communication within a species.

        Thick, short, fine hairs/setae giving a velvety appearance; in construction/building, a cylindrical/flat member of wood/steel/concrete/etc. that is hammered vertically into soil to form part of the foundation.

        A mass of building piles considered collectively with a pile being a cylindrical/flat member of wood/steel/concrete/etc. that is hammered vertically into soil to form part of the foundation.

Pilis dentilis
        In mites (Acari), the bristle attached to the inner surface of the immovable member/digit of the chelicerae (mouthparts).

Pinaculum (pl. pinacula)
        In larval Lepidoptera, a small, flat wartlike (scierotized/thickened) area bearing 1-4 setae (hairs).

Plantar bristles
        In adult fleas (Siphonaptera), the bristles located on the tarsal segments.

        A member of the insect order Homoptera, superfamily Fulgoroidea, characterized by the antenna borne on the sides of the head between the eyes, the beak usually short and rising at the back of the head, 4 wings with front wings slightly thickened and its 2 anal veins meeting distally to form a Y-vein, middle coxae elongate and separated, and jumping insects, mostly 3/8" (1 0 mm) or less.

        Featherlike; feathery in appearance.

Pollen basket
        In adult bees (Hymenoptera: superfamily Apoidea), the concave, smooth space on the posterior tibia, fringed with hairs and functioning to hold collected pollen.

        Covered with a loose, mealy dust like the pollen of flowers; surface covered with a whitish dusting.

        Of or having more than one form.

Porosity of wood
        The state or quality of being porus (full of pores); the ratio, expressed as a percentage, of the volume of the pores or interstices (spaces between pores) of wood to the total volume of its mass.

        Hind or rear, hindmost.

Posthumeral bristle(s)
        In adult flies (Diptera), the bristle(s) on the anterolateral (front side) surface of the scutum (mesonotum) just to the inside of the humeral callus (shoulder).

        In adult flies (Diptera), the area below the scutum (rear most dorsal thoracic plate).

Postsutural arcostichal setae
        In adult flies (Diptera), the lst row of bristles to each side of the midline on the mesonotum (scutum).

        Water fit or suitable for drinking.

        In thrips (Thysanoptera), the more than one stage proceeding the adult.

        An organism that obtains its food by the periodic killing of prey organisms.

        In thrips (Thysanoptera), the inactive 3rd instar proceeding the 4th instar/pupa in the suborder Terebrantia.

Prespiracular tubercle
        In larval Lepidoptera, the wartlike (scierotized/thickened) area between the spiracle and the front edge of the prothoracic segment, bearing setae (hairs).

Presutural bristle(s)
        In adult flies (Diptera), the bristle(s) located to the side and just in front of the mesonotal/transverse suture (=behind the rear most posthumeral bristle) on the mesonotum.

Pretarsus (pl. pretarsi)
        The 6th or terminal leg segment, usually consisting of 2 claws and one or more padlike structures.

Primary reproductive
        In termites (isoptera), the colony founding male or female derived from a winged adult.

Primary setae
        In larval Lepidoptera, those setae (hairs) with a definite arrangement, and found in all instars, including the lst instar.

        The protruding mouthpart structures of sucking insects; a beak.

        The insect or object when viewed from its side.

        A fleshy abdominal process, occurring in pairs, used for locomotion in larvae of butterflies and moths (Lepidoptera), and sawflies (Hymenoptera).

Pronotal comb
        In adult fleas (Siphonaptera), a row of strong spines located on the pronotum’s posterior margin.

Pronotal shield
        An expanded pronotum.

        The dorsal or top surface plate of the prothorax.

        In adult Hymenoptera, the first abdominal segment when fused with the thorax.

        In mites (Acari), the plate just behind the mouthparts and between the I st pair of legs.

Protealytic enzymes
        Protein-splitting enzymes.

        The first or front segment of the thorax, bearing the first pair of legs and without wings (except for order Strepsiptera).

        In mites (Acari), the normal 2nd instar (lst=larva, 3rd=Deutonymph).

        The rear part of the foregut behind the crop and before the midgut, variously modified in insects to aid in food processing; the gizzard.

        In Hymenoptera, a group of long coarse hairs on the underside of the head in adult ants (Formicidae) and vespid wasps (Vespidae).

        Pulmonary syndrome hantavirus.

        In adult psocids (Psocoptera), the pigmented spot/cell on the front wing located along the front edge before the apex of vein R, I

        Clothed with soft, short, fine, loosely set hairs/setae; downy.

Pulvillus (pl. pulvill!)
        In adult flies (Diptera), a padlike lobe or structure beneath the tarsal claws.

        Pits or small impressions on the cuticle, like made with a pin/needle.

Pupa (pl. pupae)
        The resting or transformation stage of insects with complete metamorphosis; the developmental stage between larva and adult.

Puparium (pl. puparia)
        In flies (Diptera), the third larval instar molt skin within which the pupa is formed.

        The tergum (dorsal plate) of the last visible segment of the abdomen.

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        Female member of a reproductive caste of a social species; in termites (isoptera), a dealated, inseminated female adult or primary reproductive.

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Ray parenchyma
        In trees, the simple, blunt-ended storage cells of the spawood that are oriented radially.

        The reproduction/regrowth of a lost part.

        In adult ants (Hymenoptera: Formicidae), an individual whose crop is greatly distended with liquid food, such that the abdominal intersegmental membranes are stretched tight, which typically hang from the chamber ceiling and serve as living reservoirs.

Reservoir (animal disease)
        An animal which serves as a living storage vessel for a disease-causing organism(s) that are then transmitted to other animals by direct/indirect contact and/or by insects, ticks, mites, etc.

        Superficially netlike or made up of a network of lines.

        Relative humidity.

        The rootlike thick strands of fungal hyphae.

        In birds, a perch upon which they rest at night; in bats, the place where they rest during the day.

        In birds (Aves), the dorsal area between the wings just before the tail.

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        The softer part of the wood between the bark and the inner/central heartwood.

Satellite colony
        A secondary colony which does not contain either a queen(s) or eggs, and is connected to the parent colony.

        A flattened seta or hairlike structure.

Scale insect
        See Coccids.

        The first or basal antennal segment.

Scepular hairs/setae
        In mites (Acari), the dorsal pair of hairs/setae to either side about midway between the midline and lateral margin, approximately in line with the 2nd pair of legs.

        A organism that feeds on dead or decaying plant or animal materials, or on animal wastes; larvae which feed on grain only after the seed coat has been broken, either mechanically or by some other insect (stored product pests).

Scent glands
        In bugs (Heteroptera), the opening to the gland located on each side of the thorax between the 2nd and 3rd pair of legs.

        Any plate of the body wall bounded by membrane and/or sutures.

        Hardened cuticle through scierotization, involving the development of crosslinks between protein chains.

Scolus (pl. scoli)
        In certain moth (Lepidoptera) larvae, tubercles in the form of spinose projections of the body wall whose spines are sometimes urticaceous/stinging.

        In adult flies (Diptera), the rear tip (often triangular) of the metathorax; in adult beetles (Coleoptera), the triangular part of the mesothorax between the bases of the slytra.

Scutum (pl. scuta)
        Any shield-shaped plate; the dorsal shield just behind the mouthparts of ticks and mites (Acari); in adult flies (Diptera), the middle division of the thoracic notum, just in front of the scutellum.

Seasoned wood
        Wood that has had its wood moisture content reduced to 19% or lower.

Secondary colony
        In termites (Isoptera), a colony of subterranean termites existing above ground which is made possible by a stable above-ground moisture source.

Secondary pest
        Insects and mites which feed on food materials which are in poor condition, usually damp and/or have some mold growth present.

Secondary reproductive
        In termites (Isoptera), reproductives which developed from nymphs; nymphoid reproductive.

Secondary setae
        In larval Lepidoptera, numerous setae (hairs) scattered over the cuticle, not constant in number or position, often occurring in tufts; usually absent in lst instar and often defensive in function.

Seed tick
        The first instar tick (Acari).

        A subdivision of the body or of an appendage between joints or areas of flexibility.

Seminal receptacle
        In female mites (Acari), the structure which receives the sperm of the male.

        In chiggers (Acari), the long hairlike structures which have 6-8 branches in their outer half located on the outer half of the dorsal shield.

        Snakelike in appearance.

        Sawlike, with notched edges like the teeth of a saw blade; in spiders (Araneae), the serrate/toothed claws on the tarsal tip.

Seta (pl. setae)
bristle; a scierotized hairlike projection.

Setal comb
        Tufts of hairs (setae).

Setula (pl. setulae)
        In fly larvae (Diptera), very small bristles or cone-shaped processes on their ambulatory areas.

        Preformed building material consisting of usually 1" (24.5 mm) or less thickness of plaster covered with paper, coming in 4 ft x 8 ft (1.2 m x 2.4 m) sheets, and attached to wall studs and coiling joists; plasterboard.

        In mites and ticks (Acari), a sclerotized or hardened plate located dorsally or ventrally; in insects, it is usually located on the dorsal half of a segment.

        Unmodified by any condition causing complexity; not forked, toothed, branched, or divided.

Simple eye An eye consisting of a single lens; an ocellus.

Simple metamorphosis In insects, development in which there is no pupal stage. Sinuous Undulating, curved in and out.

Social insect
        An insect belonging to a group in which individuals display all of the following traits: cooperative care of the young; reproductive division of labor, with more or less sterile individuals working on behalf of the reproductives; and an overlap of at least 2 generations.

        The wood of evergreen or conifer trees.

Species (pl. species)
        Fundamentally similar individuals who interbreed and produce offspring, but who do not ordinarily interbreed with other groups.

Spermatheca (pl. spermathecae)
        The sperm storage organ located in the female abdominal cavity; the receptacle of sperm during copulation.

packet of sperm; in springtails (Collembola), it is deposited on the ground/or surface by the male and picked up later by the female.

        Young/immature spiders, often used to refer to the just-hatched or lst instar spiders.

thornlike process of the cuticule not separated from it by a joint.

        In spiders (Araneae), the small tubular appendages located on rear/posterior end of the abdomen below the anus from which silk threads are extruded; in larval insects, they are usually located on the labium (lower lip).

        Armed with throny spines.

        The external opening of the tracheal (respiratory) system.

        A corkscrew-shaped bacterium, belonging to the order Spirochaetales.

        In fungi, the single-cell reproductive body.

        Fungal fruiting bodies which produce spores.

        Pigeon nestling, marketed when full grown but still unfledged (unable to fly).

Squama (pl. squamae)
        Any scalelike sturcture; in adult flies (Diptera), a calypter which is one of 2 basal lobes located at the base of the wing along the rear margin.

        Sexually transmitted disease.

Sternal shield
        In mites (Acari), the sclerotized/hardened ventral plate located adjacent to the mouthparts and I st pair of legs.

Sternum (pl. sterna)
        A hardened body wall plate on the ventral or bottom side.

Stigma (pl. stigmata)
        In mites (Acari), an opening to the respiratory system.

        In Hymenoptera, the modified ovipositor used for injecting venom; in scorpions (Scorpions), the modified terminal abdominal segment (=telson) used for injecting venom.

Stria (pl. striae)
        Any long, fine impressed line; in adult beetles (Coleoptera), the longitudinal depressed line or furrow, often punctured, running the length of the elytra (wing covers); in mites (Acari), the almost parallel fine impressed lines/grooves on the body surface.

Structural/dimension lumber
        Wood which is at least a 2x4".

        Slender projecting, nonarticulated (unsegmented), process or prolongation.

        A small, slender style or stiff process.

Stylus (pl. stylle)
        Fingerlike processes; a small, pointed, nonarticulated process.

Subantennal suture(s)
        In certain insects (e.g. adult flies/Diptera), the impressed line(s)/groove(s) extending from the antennal bass downward toward the mouth to the subgenal suture.

        In winged mayflies (Ephemeroptera), the winged developmental stage immediately before the reproductively mature adult (imago).

Submarginal cell
        In adult Hymenoptera, one or more calls of the wing located immediately behind (rearward) the marginal cells.

        Somewhat spinelike, not quite spinalike or spine-shaped.

        Impressed line/groove/furrow marking the line of fusion of 2 formerly distinct plates; the line of juncture of elytra, tegmina, or hemielytra.

        A winged reproductive; in ants (Hymenoptera: Formicidae) and termites (Isoptera), a member of the mass exodus of winged reproductives from the nest for the mating flight; in honey bees (Hymenoptera: Apidae), a member of the mass of workers and queen which suddenly leave the colony to start a new colony.

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        In myth, the frenzied dance preformed by people who thought they had been bitten by a large European wolf spider which took its name from the city of Taranto in Italy.

Tarsi appearing
        In insects, when 1 or more tarsal segments are very small and/or partially hidden by an ajoining segment such that they are present but difficult to see/detect.

Tarsus (pl. tarsi)
        The 5th leg segment, located immediately beyond the tibia, and often subdivided into "segments."


        One who studies/practices the science of identification, naming, and classification of organisms.

Tegmen (pl. tegmina)
        The hardened leathery front wing usually with reduced venation of Blattodea, Mantodea, Orthoptera, and certain Heteroptera.

Tegula (pl. tegulao)
        A scierite/plate at the extreme base of the front wing costa, being very large and overlapping the wing base in Lapidoptera and being well-developed in the Hymenoptera and Diptera.

        In scorpions (Scorpiones), the narrow last 5 taillike segments of the abdomen ending in a sting.

Temperate region/zone
        That part of the earth’s surface having a climate that is warm in the summer, cold in the winter, and moderate in the spring and autumn; area between the tropic of Cancer and Arctic Circle in the Northern Hemisphere or between the tropic of Capricorn and the Antarctic Circle in the Southern Hemisphere.

        The part of the head behind the compound eyes (Coleoptera/beeties).

        In springtails (Collembola), the clasplike structure with 2 divergent prongs located medially on the venter of the 3rd abdominal segment that serves to hold the furcula (the forked spring).

Tenant hairs
        In mites (Acari), the suckerlike adhesive hairs/setas located on the tip of the tarsi in some species.

        In slugs and snails (Geophila), the tubercle/stalk on the head that often bares an eye at its tip, usually 2 pairs present.


        A dorsal scierite or plate; the dorsal part of a segment.

Tergum (pl. terga)
        The dorsal/top surface plate of an abdominal segment.

        Located at the tip, end, or extremity.

Thorax (adj. thoracic)
        The middle body region which bears legs and wings, if present.

Tibia (pl. tibiae)
        The 4th leg segment, located between the femur and the tarsus.

        Flax, hemp, or jute fibers.

Trachea (pl. tracheae)
        The small tubes of the insect’s breathing/respiratory system which open externally at spiracles.

        In bats (Chiroptera), the leaflike structure located in the ear.

        Almost clear but slightly milky.

Transverse suture
        See mesonotal suture.

        Four-sided, having 2 sides parallel (1 side usually shorter than the other) and 2 sides nonparallel (usually of equal length).

        In mites (Acari), the normal 4th stage in development (lst=egg, 2nd=larva, 3rd=protonymph, 5th=adult).

        The 2nd leg segment, located between the coxa and the femur.

Trophallactic fluid
        A glandular fluid given by larvae to adults after being fed.

Tropical region/zone
        The surface area of the earth bounded by the two latitude parallels of 23.5’N (tropic of Cancer) and 23.5’S (tropic of Capricorn) of the equator.

        Square or broad at the end, as if cut transversely.

        A small knoblike/wartlike rounded protuberance or lobe.

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        A sore open to the surface of the body accompanied by the disintegration of tissue, the formation of puss, etc.

ULV application
        Ultra low volume application.

        In chiggers (Acari), the external opening to the respiratory system that is always associated with the coxae of the lst pair of legs.

Urogomphi (sing. urogomphus)
        In beetle larvae (Coleoptera), the usually paired process from the posterior end of the tergum (dorsal plate) of the 9th abdominal segment, being either jointed and movable or unjointed and nonmovable.

Uropod (pl. uropoda)
        Any abdominal appendage of arthropods; in Crustacea, one of the terminal pair of abdominal appendages, usually lobelike.

Urticaceous spines/hairs
        In certain caterpillars (Lepidoptera) and adult insects, hairs/setae or spines connected to cutaneous poison glands, through which venom issues (=stinging hairs); or barbed hairs/setae which cause mechanical irritation.

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        Of several colors in an indefinite pattern.

        The intermediate host; an organism that transmits a pathogenic virus, bacterium, etc.

        A thickened line in a wing, often darkened; a thin, tubular structure supporting the wing membrane.

        The pattern of veins in a wing; the complete vein system in a wing.

        Pertaining to the belly or underside; lower or underneath.

        On the underneath/lower surface and to one side of the midline.

        A animal having a backbone or spinal column.

        The top of the head between the eyes (compound eyes in adults), frons/face, and occiput (back of head).

        Oriented or going up and down, top to bottom; being upright or perpendicular to the horizon.

Vertical front ridge
        In adult flies (Diptera), the raised line that goes around the antennae bases.

Vesicular dermatitis
        Small blisters on human skin.

        Greatly reduced in size from what is typical or normal for that structure; poorly developed.

Vibrissae (sing. vibrissa)
        Long whiskers; stiff tactile hairs.

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Weep hole
        An artificial hole left in masonry walls in the mortar area for the purpose of allowing water vapor to escape.

        A member of the insect order Homoptera, family Aleyrodidae, characterized by being very small (about 1/16-1/8"/ 2-3 mm), body covered with a white powder, hind wing almost as large as front wing, wings held horizontal over body at rest, antenna 7-segmented, and tarsi 2-segmented.

        A ring of hairs set about a joint or center like the spokes of a wheel; in snails (Geophila), a complete circle of the shell.

Wing pads
        The encased undeveloped wings of nymphs which appear on the meso- and methorax as 2 flattish structures.

Wing scale
        In termites (Isoptera), the small basal portion of the wing remaining attached to the adult after the main portion of the wing is shed along the fracture line (basal suture).

Wood moisture content (WMC)
        The moisture content of the plant’s cell walls.

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