H. C. FALL 441 



antennae are sometimes entirely pale as in tridens, hut more often 

 some of the outer joints are in part dusky, the darker femoral 

 spots or clouds more often present, the elytral striae as a rule 

 slightly more impressed, the punctures a little coarser. 



These differences are all rather trifling and I have been strongly 

 inclined to place the present form as a variety of tridem; there, 

 however, does not seem to be any definite evidence of this connec- 

 tion, and as the vast majority of specimens are sharply se})arable 

 by color characters, and are held to be distinct in nearly all col- 

 lections I have examined, it is perhaps wisest to so consider them 

 for the present. It is very easy to imagine the broad fasciae of 

 tridens the result of the enlargement and confluence of the usual 

 elytral spots, and indeed the humeral spot is frequently isolated 

 by the interruption of the basal fascia, and the middle marginal 

 spot is also often fairly well defined by a narrowing or an emar- 

 gination of the posterior fascia, but never seems to lose its 

 connection with the adjacent spots. In one or two of the many 

 specimens of obsoletus before me the elytral spots are so far con- 

 nected as to approach very closely the adjacent extremes of the 

 tridens form, but even in these there is lacking something of that 

 sharpness of outline so characteristic of the latter. Normally, 

 and indeed almost without exception in obsoletus the sutural 

 interspace of the elytra — so far as it is clearly defined — is wholly 

 or largely yellow, thus interrupting the posterior fascia. In 

 tridens this fascia is not interrupted and the suture is entirely 

 black from the base to the apical yellow blotch. Here as in 

 tridens the width of the front between the eyes and the distinct- 

 ness of the ocular lines is somewhat variable. In a considerable 

 number of specimens, for the most part females from west of the 

 Mississippi, the maculation is not black but varies from fuscous 

 to pale brown. 



This species has been identified by Bowditch as peccans Suffr., 

 but incorrectly so. The two species are very easily separable if 

 males are at hand, the front claws being very distinctly enlarged 

 in peccans, while in the present species they are scarcely at all 

 larger than those of the middle and hind feet; some females, 

 however, are not so easy to distinguish. 



TRANS. AM. ENT. SOC, XLI. 



