266 



The non-sexual characters that I find to be most reliable for 

 distinguishing species are in the basal structure of the pronotum 

 (this character is recognised by Dr. Erichson in the "Insecten 

 Deutschlands " for sub-dividing Onthophagus), the size and 

 structure of the eyes, the coloring (metallic or non-metallic) of 

 the surface, the puncturation (which does not usually vary 

 sexually to any considerable extent), the presence or absence of 

 pilosity on the upper surface, and the structure of the claws. 



For tabulating the genus, as regards its Australian species, I 

 adopt six divisions founded primarily on the structure of the 

 base of the pronotum, which assumes four dififerent forms, and 

 secondarily on the structure of the eyes. 



In the first group the lateral gutter and marginal raised 



edging of the pronotum pass evenly across the base without the 



lateral edging becoming enfeebled close to the hind angles, and 



the eyes are wide, nitid, and not perceptibly facetted on the 



urface. 



In the second group the base of the pronotum is as in the first 

 group, except that the raised edginoj is suddenly and notably 

 enfeebled close to the hind angles, while the eyes are as in the 

 first group. 



In the third group the structure of the pronotum is as in the 

 second group, but the eyes are very distinctly facetted. 



In the fourth group the base of the pronotum is not strictly 

 speaking margined, but it is visible as a narrow more or less 

 flattened band, — this pseudo-margin being most conspicuous 

 when looked at obliquely from behind. The eyes are variable in 

 structure. 



In the fifth group the base of the pronotum has no gutter or 

 flattened space but is bordered by a more or less defined raised 

 edging. In many instances care is necessary in examining this 

 edging to avoid confusing it with a fine carina-like projection 

 hindward on the hind face of the base of the pronotum which is 

 present in (at least most of) the Onihophagi and seems to be 

 related to a depression on the front face of the elytra. The eyes 

 in this group are variable in structure. 



In the sixth group the base of the pronotum is absolutely even 

 and is not bordered by any gutter, raised line or depression. 

 The structure of the eyes is variable. 



It would be possible to increase the number of groups by three 

 if full use were made of the characters of the eyes in Groups 4, 

 5, and 6 ; but as this would remove into different groups species 

 that seem too closely related for such separation I have contented 

 myself with the six groups specified above. As it is, there are 

 species which seem to connect Groups 4 and 5 rather closely with 

 iGrroup 6, but such overlapping is almost always met with in the 

 division of an extensive genus into groups. 



