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with a deep transverse impression; antennae slender, witli 4^ 

 joints punctured, remainder sericeous; nth joint not appen- 

 diculate; r^' with antennce longer, and 5th ventral Inroad ly and 

 deeply emarginate with angles acute (valida only) 



E. — Prothorax ciuadrate, slightly narrowed in front, not constricted, but only 

 feebly impressed behind, elytra feebly narrowed from the base, 

 slightly truncate at tip; palpi as in B, with the last joint feebly 

 dilated, truncate, and longer than the preceding; head suddenly 

 narrowed behind, but not constricted, very short hind angles, 

 rounded ; antennae with 4^^ joints punctured, the remainder 

 sericeous, nth joint (^ very strongly appendiculate, 7th and 

 following with a smooth, feebly carinated line beneath. 



(mntabilis, etc.) 



F. — Prothora.x constricted before and behind, wider at base, hind angles not 

 prolonged; elytra wider, parallel, rounded at tip; head suddenly 

 narrowed far behind the eyes, but not constricted; hind angles, 

 therefore, long, broadly rounded; ifj'^.y wc/ emarginate; antenna 

 inserted a little behind the front margin of the eyes, slender, with 

 4>^ joints punctured, remamder sericeous, nth joint simple; 

 ' genie rather short, palpi with the last joint triangular, truncate, 

 as in vittata. This group differs from Acmceops, chiefly by the 

 position of the antennae (cubitalis only) 



A a. — Prothorax strongly narrowed from the base, which is broadly but 

 deeply bisinuate, posterior transverse impression distinct; elytra 

 widest at the base, gradually narrowed behind, truncate and 

 emarginate at tip which is not margined . (emarginata to rubida) 



A b. — Prothorax nearly smooth, strongly and gradually narrowed from the 

 base, which is bisinuate, hind impression very deep; elytra very 

 coarsely punctured, not narrowed, very dehiscent, rounded, 

 subacuminate and distinctly margined at tip . (cruentata only) 



A c. — Prothorax punctured, without hind impression, campanulate, but sub- 

 quadrate, hind angles small (except ai)iericana)\ elytra parallel, 

 genie very short (chalybsea, haematites, etc.) 



A d. — Prothorax transversely depressed at the base, convex, much rounded 

 on the sides before the middle, hind angle small (except in iin- 

 piira)\ elytra at base wider than prothorax, more or less narrowed 

 behind, usually black, spotted or banded with yellow; genae 

 moderately long (shorter in last two) . . (laeta, cordifera, etc.) 



A e. — Prothorax longer than wide, subcampanulate, with a deep transverse 

 unpression near the base, hind angles broad, laminate; color 

 black, elytra sometimes testaceous, scarcely narrowed behind; 

 antennce with 4th joint very short .... (brevicornis, etc.) 



A a. 



Antennte feebly serrate; 5th ventral rf flattened, broadly truncate-emarginate 



and bidentate; mouth short, hind angles of head more prominent. 



Black, velvety pubescent; elytra red, with apex black. 



Elytra not sulcate, prothorax sparsely punctured .... emargfnata. 



Elytra sulcate; prothorax densely punctured gigas. 



