Ambient vein: Diptera; the costal vein when it extends beyond the apex and practically margins the wing.
Ambrosia: bee-bread: the food cultures of certain Scolytid beetles.
Ambulatoria: that series of Orthoptera in which the legs are fitted for walking only; Phasmids.
Ambulatorial: fitted for walking or making progress on the surface.
Ambulatorial setae: specialized hairs or bristles, situated on the ventral segments of the abdomen of some Coleoptera. Ambulatory: moves by walking; formed for walking.
Ametabola -ous: insects without obvious metamorphoses, in which the larvae usually resemble the adult and the pupae are active.
Ametabolion: an insect that has no distinct metamorphoses.
Amethystine -us: bright blue with a reddish admixture; clear like an amethyst [between mauve and lilac].
Amnion: the inner of the two membranes enveloping the embryo.