Coxa -ae: the basal segment of the leg, by means of which it is articulated to the body.
Coxal cavity: the opening or space in which the Coxa articulates; in Coleoptera the cavity is open when the epimera do not extend to the sternum; closed or entire when the epimera reach the sternum or join medially as in Rhynchophora; the cavities are separated when the prosternum extends between them, confluent when it does not: see acetabulum.
Coxal glands: eversible glandular structures at base of legs; well developed in some Thysanurans, modified variously in higher orders.
Coxal stylets: short, leg-like, jointed appendages on the underside of the abdominal segments in Thysanura.
Crag: the neck: = cervix.
Cranium: the head or skull except the neck; sometimes limited to the fixed parts above the clypeo-frontal suture.
Crassus: thick; tumid.
Crateriform: like a shallow funnel or deep bowl.
Creber: closely set.
Cremaster: a stout spine, process or hooked area at the hind end of pupae in Lepidoptera.