AMERICAN COMPONENTS OF THE TENTYRIIN^ 4I I 



more angulate humeri, only a fourth wider than the prothorax and 

 more than three times as long (9) or much less ((^)<, with the 

 impressetl lines feeble suturally ( 9 ) or obsolete ((^), the punc- 

 tures rather coarse and moderately close suturally, not coarser and 

 but little closer laterally though less deep. Length 10.5-11.0 

 mm.; width 4.9-5.3 mm. Mexico (Guadalajara), — R(j11c. 



* obsolescens n. sp. 



The singular structure of the upper surface of the head by 

 which tencbrosus and occipitalis are separated, is essentially a 

 female character but is never so pronounced or accompanied by 

 so much impression, opacity or reduction of the punctuation 

 elsewhere, as far as noted, although traceable in such obese 

 forms as amflijicans. It may be also noted, in this connection, 

 that the supra-orbital carina? are generally fine and feeble, some- 

 times subobsolete, but that they are almost always much more 

 developed in the female than in the male. The prothorax varies 

 sometimes rather conspicuously in size within the same sex, as 

 for example in neglectus, where in one female before me it is 

 fully two-thirds as wide as the elytra and in another, much 

 smaller, only a little more than half the width of the elytra ; 

 it may be observed also that the prothorax may be subsimilar in 

 size and outline in the two sexes or may be smaller in the female 

 than in the male, in arimdinis ^^n^ fimebris \^vy remarkably 

 so, while in acomanns and sccutor it is broader and somewhat 

 larger in the female than in the male. 



In the single apparently mature female of subrudis, a prob- 

 ably accidental character, analogous to that noticed before in the 

 case of Lobometopon uintanum occurs, both antennae being very 

 pale flavo-testaceous, becoming gradually piceous toward base 

 and contrasting greatly with the uniformly black antennae of the 

 male. The female of -pensus^ received since the original descrip- 

 tion of that species was written, is remarkably aberrant; it is 

 stouter than the male, the prothorax flattened medially at apex, 

 the flattened part deeply emarginate at apex, with the sides 

 obliquely, anteriorly projecting and prominent, each prolonged 

 longitudinally backward in a small feeble ridge, obsolete before 

 the middle, each ridge bordered internally by a feeble oval im- 

 pression ; there is nothing else like it known to me and it has no 

 appearance of being a sport or monstrosity. The single female 



