— 82 — 



BB. Head with but one bristle-bearing puncture above the eye. 



C. Elytra truncate at apex; mandibles with a bristle-bearing punc- 

 ture in outer groove; hind coxae often separated — Brachinus 

 (Bombardier beetle). 

 CC. Elytra always entire; mandibles without a bristle-bearing 

 puncture; hind coxae contiguous. 

 D. Antennae with only two basal joints glabrous ; black, 

 front tarsi of male dilated and with two rows of small 

 scales beneath; first joint of hind tarsus not longer than 

 the two following — Harpahis. 

 AA. Middle coxal cavities not entirely closed by the sterna. 



B. Hind coxae not separated; labrum not forked; third joint of an- 

 tennae cylindrical — Carabiis. 

 BB. As in B, but third joint of antennae compressed — Calosoma. 



ELATERIDAE. 



Common Genera. 



A. Hind coxal plates suddenly dilated about the middle, the outer part much 

 narrower than the inner. 

 B. Prosternum very broad, sutures straight, side pieces of mesothorax 



reaching the middle coxae — Cryptohypnus. 

 BB. Prosternum of moderate width; sutures double and not excavated in 

 front ; third joint of antennae longer than second — Drasterius. 

 AA. Hind coxal plates gradually dilated on the inner side. 



B. Clypeus or front convex and truncate, its edge higher than the labrum, 

 mouth inferior and applied to the prosternum in repose. Side mar- 

 gins of thorax bent downward in front — Agriotes. 

 BB. Clypeus of front flattened; mouth horizontal or anterior. 



C. Front margined ; tarsal claws with comb-like teeth — Melanotus. 

 CC.jFront not margined. 



D. Tarsi simple, filiform — Corynibites. 



DD. Tarsi with the second and third joints lobed beneath — 

 Asaphes. 



CHRYSOMELIDAE. 



(Leaf -beetles). 



(Adapted from Leconte and Horn). 



Common Genera. 



A. Head produced; thorax narrower than elytra; mandibles simple, pointed. 

 B. Thorax cylindrical, not constricted. — Crioceris. 

 BB. Thorax constricted. — Lema. 

 AA. Head inserted in the thorax to the eyes; thorax as broad as the elytra; 

 mandibles with several teeth. 



B. Last dorsal segment of abdomen not exposed. 

 C. Antennae widely separated at base. 



