a sac-like ventral cavity,
formed by material secreted during copulation.

Abductor: applied to muscles that open out or extend an appendage or
draw it away from the body: see adductor.

Abductor mandibulae: the muscle that opens the mandibles.

Aberrant: unusual; out of the ordinary course.

Aberration: a form that departs in some striking way from the normal
type; either single or occurring rarely, at irregular intervals.

Abiogenesis: spontaneous generation.

Abnormal: outside the usual range or course; not normal.

Aborted: a structure developed so as to be unfit for its normal function
obsolete or atrophied.

Abraded: scraped or rubbed.

Abrupt: suddenly or without gradation.

Abscissus: cut off squarely, with a straight margin.

Absconditus: hidden, concealed; retracted into another.

Acalyptrata: those muscid flies in which alulae are absent or
rudimentary.

Acanthus: a spine, spur or prickle.

Acaudal -ate: without a tail.

Accessory: added, or in addition to.

Accessory carinae: in Orthoptera the lateral carinae of the face.

Accessory cell: a cell not commonly present in the group; in some
orders of definite location as, e.g. in Lepidoptera, usually a small cell
at the end of the subcosta, giving rise directly or indirectly to veins 7
to 10:= 1st radius 2 (Comst.); = areole.

Accessory glands: any glands opening into the ducts of the
reproductive system.

Accessory sac: a glandular structure of the female reproductive
system containing a sticky secretion.

Accessory subcostal vein: the vein given off from the subcosta and
branching toward the apex of the wing in Perlidae.

Aceous or aceus: suffix; similar to, or of the nature of.

Acephalous: without a head.

Acerata: arthropods without true antennae Arachnids and Limulus

Acetabular caps: Hemiptera; the coxal cavity.

Acetabuliform: like a shallow saucer with more or less incurved sides.

Acetabulum: the cavity into which an appendage is articulated;
specifically the coxal cavity, - q.v.; also applied to a
cup-like cavity in the sucking mouth of maggots.

Achreioptera: ordinal term proposed for the coleopterous family
Platypsyllidae.

Achromatic: free from color; tissue that does not stain readily.

Acicular: needle-shaped; with a long, slender point.

Aciculate: a surface that appears as if scratched with a needle.

Acidotheca: the pupal sheath of the ovipositor.

Acini: granulations, like those on a blackberry: the t