278 CASEY 



2 — Anterior tibiae with a single terminal spur and a submedian external 

 tooth ; mandibles grooved externally throughout their length ; 

 mentum hexagonal, feebly sinuate at tip ; intercoxal process of 

 the abdomen narrow, subacute or slightly rounded; scutellum 

 distinct; metasternum with transverse ante-coxal grooves; hind 

 wings well developed Cnemodini 



Anterior tibiae with two terminal spurs, not toothed externally near 

 the middle in any American genus; mandibles never grooved 

 externally except in Erodiini 3 



3 — Posterior coxae more or less narrowly separated, the abdominal 

 process acute to broadly rounded 4 



Posterior coxae widely separated, the abdominal process broadly trun- 

 cate ; metasternum without ante-coxal grooves, short, the body 

 wingless ; elytra frequently costulate 11 



4 — Elytra not embracing the sides of the body, the inflexed parts 

 occupied wholly by the epipleurae — or epipleural "repli" of 

 Lacordaire 5 



Elytra embracing the sides of the body, the inflexed parts not wholly 

 occupied by the epipleurae 10 



5 — Mentum hexagonal, with the apex more or less distinctly emargi- 

 nate or sinuate 6 



Mentum transversely parallelogramic, the apex very broadly arcuate 

 from side to side and not sinuate at the middle, generally much 

 more transverse 9 



6 — Front without a prolonged epistoma clasped by the mandibles, the 



frontal margin transverse and more or less feebly modified, the 

 right mandible at least generally with a tooth which clasps the 

 labrum only ; antennce slender, with the outer four joints broader ; 

 scutellum well developed; metasternum with ante-coxal trans- 

 verse grooves ; body generally winged, though often apterous. 



Eurymetoponini 



Front with the epistoma abruptly prolonged 7 



7 — Epistomal lobe clasped by the superior external ridge of the man- 



dibles ; antennas filiform, generally with the last four joints larger. S 

 Epistomal lobe not clasped by the mandibles, which are folded be- 

 neath it out of sight from above ; antennae gradually enlargetl and 

 compressed outwardly Auchmobiini 



8 — Scutellum well developed as in Eurymetoponini ; body winged or 



apterous, the metasternum with or without ante-coxal grooves. 



Trimytini 



Scutellum extremely minute or obsolete ; body wholly apterous ; meta- 

 sternum always very short, without trace of ante-coxal grooves. 



Trientomini 



9 — Metasternum with transverse grooves parallel to the hind coxa', 



the body general!}' winged, the epistoma lobed and the scutellum 

 well developed Epitragini 



