CETONIINJE 277 



scutellum. The dorsal surface is more or less feebly convex, and 

 the elytra have the usual post-humeral sinus well developed. 

 The intercoxal process of the mesosternum is broad and variously 

 modified and the general surface glabrous above and beneath, or 

 nearly so, though the pygidium generally has minute stiff erect 

 hairs. There are but two genera found north of the Mexican 

 boundary, though several others, having variously modified cephalic 

 surface and clypeal apex, occur in Central America; our two genera 

 are the following: 



Clypeus simple, sinuato-truncate at apex in both sexes; mesosternal 

 process variable in form but usually reflexed and prominent; py- 

 gidium usually opaque and with peculiar abruptly incised, close 

 vermiculate sculpture as a rule. [Type Scarabceus lanius Linn.] 



Gymnetis 



Clypeus with a corniform process at the apical margin in both sexes; me- 

 sosternal process flatter and generally more horizontal; pygidium 

 usually more shining and with finer transverse wavy incised lines. 

 [Type Gymnetis nnitabilis G. & P..] Cotinis 



These two genera are very distinct in general habitus, Gymnetis 

 generally being of smaller size and with mottled or intricately 

 variegated ornamentation, except rarely in such forms as cinerea r 

 where the color is uniform; in Cotinis the color scheme is entirely 

 different, the upper surface usually being green, tawny to black, 

 with or without pallid side margins; in both genera the upper sur- 

 face is opaque as a rule, though some species of Cotinis and one 

 or two now placed in Gymnetis are polished above as well as below. 

 In two Brazilian species of Gymnetis before me, labeled minor and 

 carbonaria, but perhaps not correctly, the entire upper surface is 

 distinctly though sparsely pubescent. 



Gymnetis MacLeay. 



It is at times almost impossible to differentiate the sexes in this 

 genus, though in some species there are special marks of a sexual 

 nature, as for example in the chevrolati group, as stated above, 

 where the male is densely dull throughout the under surface but 

 largely polished in the female. I also find that in this section and 

 some others, the hind tarsi are notably longer in the male, but 

 otherwise there are no evident sexual signs whatever. There are 

 two subgeneric groups among our few species as follows: 



