American Insects Web site

True Bugs Glossary


Aedeagus. A part of the male reproductive system, in effect the phallus, which attaches to the tip of the female's abdomen during copulation.

Antenniferous tubercle. Discrete, typically cylindrical areas on the sides of the head, to which the basal segments of the antennae are attached.

Anterior Pronotal Lobe. Front portion of the pronotum, laying between the head and the posterior pronotal lobe.

Apex. The portion of a body part that is farthest of the central body or from the base. The apex of an antenna is the tip. The apex of the pronotum is the part nearest the head. The apex of the abdomen is the posterior (rearmost) portion. The plural of apex is apices. The opposite of apex is base.

Apical. Pertaining to the apex.

Basal. Pertaining to the base.

Base. The portion of a body part that is closest to the central body and farthest from the apex. For example, the base of an antenna is the part nearest the head. The opposite of base is apex.

Beak. The most obvious part of the piercing-sucking mouthparts found in Hemiptera. Same as Rostrum.

Bivoltine. Producing two broods per year.

Brachypterous. Having small, rudimentary wings. In many species of True Bugs there is both a fully winged form and a brachypterous form.

Clavus. Part of the hemelytra that lies next to the scutellum when the wings are folded. The plural of clavus is clavi.

Claval commissure. The line where the two clavi meet; lies to the posterior of the scutellum. See illustration below.

Hemiptera anatomy chart, True Bugs, Clavus, Corium, etc.

Collar. The most anterior part of the pronotum, a narrowed area typical separated from the pronotum by a groove.

Congener. Said of a species that is in the same genus as the species at hand.

Connexivum. Edge of the abdomen, sometimes visible when the insect is at rest. The connexivum may be flat, or it may be reflexed upward. In some cases it is banded in alternating colors. See photo below.

Cuneus and Connexivum, glossary illustration

Corium. The part of the forewing lying between the clavus and the membrane when the insect is at rest. See top illustration on this page.

Cuneus. Small triangular area of the wing, typically reflexed downward, seen in the Plant Bugs, family Miridae. See photo above.

Discal cells. Wing cells that are near the center of the wing and that do not reach a wing margin.

Diurnal. Active during the day; the opposite of diurnal is nocturnal.

Dorsal. Pertaining to the dorsum.

Dorsum. The "back" of the insect. Typically the dorsum is seen in a bird’s eye view of the insect.

Edges. The side margins of a structure, such as the forewing.

Elytra. Occasionally used to refer to the thickened part of the Hemelytra.

Face. The head's front aspect, often roughly perpendicular to the vertex portion of the head.

Femur. The first elongate leg segment visible in a dorsal view. Moving apically, the femur is attached to the tibia which is then attached to the tarsi. The plural of femur is femora.

Instar. A period in the life of a nymph, either between hatching and the first molt, or between two molts.

Hemelytra. The front wings, which are partially membranous, partially thickened. The singular is hemelytron.

Juga. The head's lateral lobes; see illustration photo near the bottom of this page. Between the juga is the tylus. The singular of juga is jugum.

Larva. An immature insect. Traditionally this term has been reserved for groups like Beetles that have complete metamorphosis; the term nymphs has traditionally been used among Heteroptera and other groups with incomplete metamorphosis.

Longitudinal. Going in the "length" direction on the bug as opposed to the "width" direction. For example, the claval commissure is longitudinal. The opposite of longitudinal is transverse.

Margins. Same as edges; the sides of structures such as the forewings.

Membrane. The translucent tips of the hemelytra.

Nearctic. Biogeographic region that includes Canada and the United States. In its most precise form small parts of the southernmost United States are included in the Neotropics rather than the Nearctic.

Neotropics. Biogeographic region that includes the West Indies, Mexico, Central, and South America.

Nymph. An immature; the stage of life between the egg and the winged adult.

Oblique. At an angle; neither horizontal nor vertical; diagonal.

Ocelli. Simple eyes. Much smaller than the pair of compound eyes. Their number and location is used in some keys to family and subfamily in the True Bugs. The singular of ocelli is ocellus.

Ostiole. The scent gland opening.

Posterior Pronotal Lobe. The rear half of the pronotum, lying between the anterior pronotal lobe and the scutellum. See the top photograph on this page.

Pronotal lobe. One of two main areas of the Pronotum. See Pronotum, Anterior Pronotal Lobe, and Posterior Pronotal Lobe.

Pronotum. The large dorsal plate between the head and the scutellum.

Reticulate. Forming a net-like pattern. For example, a pattern of veins and cross-veins that form numerous rectangles is said to be reticulate.

Rostrum. The beak; the most noticeable part of the piercing-sucking mouthparts of True Bugs.

Scutellum. The often-triangular dorsal plate behind the pronotum and usually between the bases of the hemelytra.

Scutellar suture. A small line in the transverse direction on the scutellum, typically near the center.

Setae. Bristles, stiffened hairs. The singular of setae is seta.

Setose. Bearing setae.

Sinuate. Said of a line or an edge that is wavy.

Striae. Longitudinal lines on a hemipteran.

Striate. With striae present.

Striations. Same as striae.

Tarsus. The apical section of the leg; the "foot." At its basal end the tarsus is attached to the tibia. The plural of tarsus is tarsi.

Teneral. An adult insect that has recently molted, and is typically soft and light-colored and not yet capable of flight.

Tibia. The shin; the middle section of the leg located between the femur and the tarsus. At its basal end the tibia is attached to the femur; at its apical end the tibia is attached to the tarsus. The plural of tibia is tibiae.
Anatomical illustration: tylus, juga, antenniferous tubercle

Transocular width. The space on the dorsum of the head between the two compound eyes.

Transverse. Going in the "width" direction on the insect as opposed to the "length" direction. For example, the base of the pronotum runs in a transverse direction. The opposite of transverse is longitudinal.

Tylus. Area between the juga; see photo at right.

Univoltine. Producing one brood per year.

Vertex. The doral surface of the head (excluding the eyes).

This Hemiptera Glossary is a part of the American Insects web site. Text and photographs © 2011.