364 Trans. Acad. Sci. of St. Louis. 



base, each is hollowed into a concave helicoidal polished sur- 

 face, permitting of the easy motion of the broad prothorax 

 upon them ; externally this helicoidal surface is vertically 

 and prominently carinate, this also being a unique feature. 

 The punctuation of the elytra and abdomen is minute and 

 very close-set, the pubescence short but conspicuous. 



The species serving for this diagnosis is one sent me re- 

 cently from Egypt by Mr. Keitter, under the name beduinus 

 Nord. In spite of its conspicuous eyes it is probably virtually 

 blind. It is evident, on considering the strongly and eccen- 

 trically dilated anterior tarsi and general facies, that Platy- 

 prosopus is a very aberrant member of the present tribe, 

 forming one of its bonds with Pinophilua. 



Subtribe Xantholini. 



This subtribe of almost mundane distribution embraces by 

 far the greater part of the tribe. From such evidence as is 

 available its numerous genera appear to be clearly delimited 

 and in no way opinionative, which suggests a comparatively 

 great antiquity for the subtribe as a whole. It possesses this 

 character in common with the Paederini and Pinophilini, in 

 contrast with the Stenini and some other groups, which seem 

 to be in a more decidedly mutative state at the present time. 

 One of the most striking features of the subtribe under con- 

 sideration and one by which its genera can always be recog- 

 nized at a glance, is the very remarkable and almost unique 

 form of the elytral suture, the double beveling giving the 

 effect of gemination as explained in the table of subtribes. 

 This character is found elsewhere only in the Araeocnemes 

 and Metoponci, but to a much less developed degree. The 

 middle coxae are more or less widely separated as a rule, 

 sometimes very remotely so as in LeptoUnus, but in Idiolinus 

 they become contiguous, so that the contiguity of the coxae, 

 which prompted LeConte to place the minute Jioridanus in 

 Metoponcus, is therefore not necessarily a bar to its reception 

 within the subtribe Xantholini. Those genera having a 

 smooth pronotum, devoid of the medial dorsal series charac- 



