KEY TO THE ORDERS 



289 



BBBB. Tarsi variable, antennae club-shaped; i.e., the distal 

 joints enlarged; or antennal joints from third outward inure 

 or less saw-like, the saw-teeth being on the inner edge. 

 (Polymorpha. ) 

 C. Tarsi five- jointed. 



D. Maxillary palpus as long or longer than the antennre. 



Hydrophilidae. 



( Water Scavengers.) 



DD. Maxillary palpus plainly shorter than the antennae. 

 E. Abdomen with seven or eight visible ventral seg- 

 ments. Integument soft. Lami>ijfi<lm i . 



(Lightning-Bugs.) 



EE. Abdomen with five visible segments ; integument 

 firm. 



F. Anterior coxae globular, and projecting but little 

 from the coxal cavities. 



G. Hind angles of prothorax more or less prolonged 

 backward. Prothorax fitting loosely to the after- 

 body, thus admitting free nodding movements. 



Illdtcridae. 

 (Click Beetles.) 



GG. Hind angles of prothorax not prolonged back- 

 ward. Prothorax fitting closely to after-body, per- 

 mitting no nodding motion. Bii]ircKti/l>i<. 



(Metallic Wood-Borers.) 



FF. Anterior coxa? conical, i. c., long, oblique, and 

 projecting prominently from the coxal cavities. 

 Small or moderate-sized beetles. Dcnm.^l iilne. 



(Carpet Beetles ; Buffalo Moths.) 



CC. Tarsi apparently three-jointed (the apparent third 

 joint consisting really of two small segments). 



Coccincllidae. 

 (Ladybirds.) 



CCC. Tarsi variable, being three-, four- or five-jointed. 

 D. Abdomen flexible, with seven or eight segments visible 

 below ; elytra very short, leaving greater part of abdomen 

 exposed. Stapluiliniilnr. 



(Rove Beetles.) 



DD. Abdomen firm; elytra usually covering the body; 

 (the elytra of some Silphidse are short, exposing at most 

 the last three dorsal segments of abdomen.) 

 E. Legs fitted for swimming. C! i/rinidac. 



19 (Lucky-Bugs; Whirligig Beetles.) 



