Coelom-sac: the cavity containing the viscera: in embryology one of a pair of closed sacs, arising in the mesoderm of each segment of the embryo and giving rise to more or less of the coelom of the adult.
Coenogonous: oviparous at one season of the year, ovoviviparous at another, as in Aphididae.
Coeruleus -eous: sky-blue: see caeruleus.
Coincident: when two wing veins run together or lie, one in continuation of the other so as to appear like one.
Coleoptera: sheath-winged: an order with the primaries coriaceous, used as a cover only, meeting in a straight line dorsally; mouth mandibulate; pro-thorax free; transformation complete: the beetles: the term has also been applied to the two elytra together.
Collar: in general any structure between the head and thorax: specifically, in Hymenoptera, the neck; in Diptera, may mean the neck, the sclerites attached to the thorax, the thorax itself, or its processes (ante furca): in Coleoptera, is the narrowed thorax; in Lepidoptera, applied to the sclerites attached to the thorax and which shield the neck.
Collembola: an ordinal term applied to species which are apterous; have no metamorphoses; have variably developed abdominal saltatorial appendages and a peculiar ventral tube at base: the spring-tails.
Colleterial gland: see Colleterium.
Colleterium: a glandular structure accessory to the oviduct, secreting the viscid material used in cementing the eggs together.
Collophore: the sucker-like organ extended from the underside of the abdomen in Collembola.