122 Coleopterological Notices, 



the female they are more than twice as long and stout as in the 

 male, being extremely minute in the latter sex. 



The discovery of this peculiar secondary sexual character proves 

 that these terminal setae play a more important part in the economy 

 of the insect than has been hitherto supposed, and that the gap 

 separating those genera possessing them from those in which they 

 are wanting, as for instance Stilbus and Olibrus, is even correspond- 

 ingly greater. It also indicates that any classification of the species 

 in genera possessing these setae, based in any way upon them, must 

 be used with more or less caution. It is only fair to state, however, 

 that I have not been able to discover similar sexual variation in 

 Stilbus, where I have separated several species because of the abnor- 

 nal shortness of these setae, and in this particular case it is of very 

 little consequence, as the four species constituting the second group 

 are so distinct in other characters that they can be easily identified, 

 and after all this is the main object of taxonomical tables in such 

 preliminary and superficial studies as the present is necessarily 

 forced to be. 



The terminal setae in A. calcaratus also differ sexually, but only 

 to a slight degree, being a little longer in the female ; they are, in 

 that species, very persistently two in number. 



Besides being aberrant in this way, the present species differs 

 greatly in coloration from the others, reminding us somewhat, but 

 in facies only, of Stilbus vidnus. It also appears to resemble the 

 Central American Olibrus submaculatus Sharp, especially in colora- 

 tion, but the sculpture and punctuation seem to be much more pro- 

 nounced and evident than in that species. 



LIOPHALACRUS Sharp. 



The single specimen of the typical L. bicolor before me is in a 

 very imperfect state, so that I cannot examine the mouth-parts or 

 antennae ; otherwise it is extremely closely allied to Stilbus, and 

 differs only in the structure of the posterior tarsi, which are com- 

 paratively short and slender, cylindrical, with the proportional 

 length of the joints as in Stilbus, but with the first joint rigidly 

 anchylosed to the second. The second joint is not remarkably long, 

 and not quite twice as long as the first, the third being slightly 

 dilated and deeply emarginate above. In Stilbus the articulation 



