142 MEMOIRS ON THE COLEOPTERA 



surface. The elytral punctures of mmdum are much less coarse 

 than in either prosperum or luculentum, these two being mutually 

 distinguishable by the smaller head, and smaller and differently 

 shaped prothorax of luculentum. Constrictum seems to be more 

 essentially a maritime species, or at least I have seen no specimens 

 taken far from the seashore. The individually abundant, smaller 

 and narrower species, widely distributed from Lake Superior to 

 Texas, named sociale above, has doubtless been hitherto confounded 

 with constrictum; it however differs altogether in the striation of 

 the elytral apex, besides its shorter prothorax, narrower form and 

 smaller size; at its southern limit of distribution, there is a form 

 taken by Wickham at Dallas, which might appear to be varietally 

 different, being somewhat narrower, flatter, with less deep black 

 elytra and a still slightly wider head ; negligens and fugitans are also 

 closely allied to sociale, but I believe them to be distinct, judging 

 by the habitus and other structural evidences, in conjunction with 

 their widely different geographic environments. 



The species allied to affine and versicolor constitute a clearly cir- 

 cumscribed section of Notaphus, which has been very inadequately 

 studied heretofore. As organized above, however, it includes three 

 well differentiated subsections, represented by affine, with parallel 

 frontal sulci, feebly transverse and basally much narrowed pro- 

 thorax and longer, very slender antennae; versicolor, with subparallel 

 sulci, broader thoracic base and less elongate and usually thicker 

 antennae, and egens and the other three associated with it in the 

 table, having strongly converging sulci, almost is in the assimile 

 group, but well separated at apex and not confluent as they are in 

 that group, and also having a somewhat different scheme of elytral 

 maculation. Cognatum Dej., is evidently allied to pulhthim, but 

 the only pale elytral markings of cognatum are the apex and a small 

 posterior external spot, and the obliquity of the frontal sulci ap- 

 pears not to be so decided, from the language used by Dejean 

 "un peu oblique." There are evidently a considerable number of 

 species allied to cognatum, of which four are described above, and 

 they may possibly be held to form a distinct section of Notaphus, 

 constituting one of its bonds with the assimile group. 



The common Texas species with large head and prominent eyes, 

 named imbelle above, extends to the northward through the Mis- 



