136 MEMOIRS ON THE COLEOPTERA 



Form narrower and more convex, cylindric-oval, shining; coloration 

 similar, except that the oblique discal vitta is not more than half as 

 wide and pale brown, and the sutural vitta becomes much dilated 

 basally; head similar, except that the front is not rugulose but dis- 

 cretely punctate, the punctures becoming gradually sparse and very 

 fine basally; clypeus densely and rather more finely punctato- 

 rugulose, much narrower in form, about two-fifths wider than long, 

 similar in outline, the edges more abruptly and strongly reflexed, 

 the suture not obliterated medially and there sinuate; prothorax 

 similar but longer, barely one-half wider than long, the apical angles 

 less acute; scutellum smaller, still more acute at apex; elytra but 

 very little wider than the prothorax, nearly a fourth longer than wide, 

 otherwise nearly similar; pygidium (cf ) similar but with the minute 

 punctures basally bearing erect hairs, which are easily distinguish- 

 able though short and fine; in obliquata they are extremely minute; 

 abdomen similar but with coarser, denser, more scabrous punctuation 

 at the sides; sternal pubescence finer and not conspicuous. Length 

 (cf) 12.8 mm.; width 6.5 mm. Mexico (Jalapa). One example. 



*emacerata n. sp. 



Both of these species, which are amply distinct between them- 

 selves, differ from complanata in their much smaller size and 

 emacerata, at least, in the more convex surface. 



Group II. 

 Subgenus Isocoryna nov. 



In many ways, as in type of elytral ornamentation, setigerous 

 punctures of the upper surface and pubescent pygidium, punctua- 

 tion of the head and tibial structure, the single species of this sub- 

 genus is much more closely allied to Cydocephala signata than it is 

 to the preceding subgenus, but the upper surface is very convex, 

 which, with the stouter oblong outline, gives it a very different 

 habitus. In the structure of the male abdomen, as stated above, it 

 is quite isolated. The type may be defined as follows: 



Body stout, oblong-oval, convex, shining; head black, the clypeus barely 

 at all paler; pronotum pale flavate, without maculation, the elytra' 

 still paler, each with three black spots, two at basal fourth, the third 

 on the median line post-medially and irregular, being transversely 

 reniform; pygidium blackish, with a nubilous red median vitta; under 

 surface throughout piceous-black, the legs castaneous, the hind 

 tibiae darker and the hind tarsi black; head small; front finely, closely 

 punctate, the punctures laterally becoming coarse, deep and setig- 

 erous; base almost smooth; clypeus one-half wider than long, trape- 

 zoidal, with feebly arcuate sides, rounded angles and broadly ar- 

 cuate, gradually and feebly reflexed, finely margined apex; erect 



