ORDBR RHYNCHOTA (HEMIPTERA) : BUGS 203 



(e\vTpov = a. sheath), and the distal half as the membrane. 

 The elytrum (Fig. 86) is composed either of two lateral 

 pieces — a smaller inner plate, or clavus, and a larger outer 

 plate, or corium ; or the tip of the corium may be separated 

 as a third distinct plate, or cuneus ; or the outer (costal) 

 edge of the corium may form a fourth distinct plate, or 

 embolium. 



The Heteroptera consist of two groups, namely, the 

 Gymnocerata {yvfivos = naked ; Kepai; = horn), in which the 



Fig. 86.— Elytrum of Bug. 



antennae are conspicuous ; and the Cryptocerata (jcpvirro^ = 

 hidden), in which the antennae are' hidden beneath the head 

 or in pits. Except for certain forms that skate about on the 

 surface of water, or that have semi-aquatic habits (and these 

 forms are distinguished by having the under-surface of the 

 abdomen covered with a dense pubescence), the Gymno- 

 cerata are land-bugs. The Cryptocerata are almost all truly 

 aquatic. 



{a) Heteroptera Gymnocerata. 



Of the many families of GYMNOCERATA we need mention 

 only the Cimicidcs, the Polyctenidce, the ReduviidcB, the 

 Aradidce, and the HydrometridcB. 



I. Family CiMiclD^. This small family includes the 

 bed-bugs. The CimicidE have a broad and rather short 

 head, a flat oval body, and short elytra that leave the 

 abdomen uncovered : the antenna is composed of 4 segments, 

 and the beak, which in repose lies in a groove, of 3 : hind 

 wings are absent, and the tarsi consist of 3 segments. 



The two notorious species are Cimex lectularius, the 

 common bed-bug of northern latitudes, and Cimex rotundatus 

 the bed-bug of the tropics. 



