Costal field: Orthoptera; that region of the tegmina adjacent to the anterior margin or costa: = anterior field. Costal fold: in the males of some Hesperidae, a membranous flap that may be opened to expose the androconia. Costal margin: the anterior margin of a wing whether it is really costate or not. Costal membrane: Hymenoptera; the surface of wing in front of costal vein. Costal vein: Lepidoptera; runs close to and parallel with the costal margin, extending from base to the margin before the apex; always simple and often absent in the secondaries; is vein 12 of the numerical series on primaries; vein 8 on secondaries: = subcosta (Comst.). Costate: ribbed; marked with elevated thickened lines. Costula: Hymenoptera; a small ridge separating the externo-median meta-thoracic area into two parts. Costulatus: less prominently ribbed than costate. Cotyla: the articular pan; the cup or socket of a ball and socket joint. Cotypes: are all the specimens before the describer when a species is named, no single one being selected as the type: the type in such case equals the sum of the cotypes: see paratype. 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. Crenate: scalloped, with rounded teeth. Crenulate: with small scallops, evenly rounded and rather deeply curved. Crepitation: a crackling sound or the production of such as by discharge of vapor or "bombarding": a cracking or creaking. Crepuscular: active or flying at dusk. Crescentiform: like a lunule or crescent. Crescentric: lunulate. Crest: a prominent, longitudinal carina on the upper surface of any part of the head or body. Crested: see cristate. Cretaceous: chalky white: the third, uppermost and latest of the three great divisions of the mesozoic or secondary rocks. Cribrate: pierced with closely set, small holes. Cribriform: with perforations like those of a sieve. Crineous: dark-brown, with a slight admixture of yellow and gray. Crinite -us: with tufts of long thin hair: see lanuginose.