182 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lo* 



Bolbocerosoma pusillum Dawson and McColloch 



Bolbocerosoma pusillum Dawson and McColloch, 1924, p. 11 (type, male, Kansas 

 (KanStU)).— Dawson, 1922, p. 194.— Brown, 1928, p. 193. 



Length 6 to 10 mm., greatest width 4 to 7 mm. 



Dorsum reddish brown marked with black as follows in male: 

 Vertex, most of clypeus, eyes, eye canthi, apical pronotal margin be- 

 tween lateral carina, lateral limiting grooves and inner portions of 

 adjacent tubercles of transverse and lateral carinae, band on pronotal 

 base very narrow at midline and extending no farther than elytral 

 margin, scutellum, extremxC base of elytra, sutural intervals, and en- 

 tire apical two-fifths of elytra extending from sutural interval to mar- 

 gin. The black area barely reaches margin, and then usually only in 

 apical fourth. Females marked as male except at pronotal modifica- 

 tion where there is only a trace of black along the transverse carina 

 and in lateral limiting grooves. Ventral sm'face of both sexes reddish 

 brown. Tibia of males edged A\'ith trace of black, females with tibia 

 usually entirely brown. Vertex coarsely, moderately punctured, us- 

 ually more so in female, punctures of clypeus generally regular and 

 dense. Pronotum coarsely, irregularly punctate, lateral portions 

 more finely, closely punctm-ed, more so anteriorly. Minute secondary 

 punctures evenly distributed over pronotum. Declivity of pronotal 

 modification in male coarsely punctured only in lower half, female in 

 some cases with some punctures over entu-e declivity. Scutellum 

 usually with faint groove running its length, with moderate number 

 of secondary punctures. Second elytral stria obsolete, represented by 

 shallow groove or two or three minute punctures. Fifth and eighth 

 striae indicated by a line of small punctures. Punctures in striae 

 usually not well delimited, generally separated by about their own 

 diameter. Many of elytral punctures and other scattered punctures 

 of elytra and pronotum bearing long erect yellow hairs. Long setae 

 also present on epipleura and elytral margins. Foretibia usually 

 armed with seven teeth on outer margin, but sometimes with eight, 

 rarely six. Mesosternal prominence only slightly developed in front 

 of middle coxae, not elevated above plane of metasternum. Hair of 

 underside long and moderately sparse. 



Head of male with tubercles of eye canthi and clypeus pronounced, 

 sharply upturned. Horn in center of vertex long, somewhat conical, 

 tip not bifid. Head of female with suggestion of a tubercle on eye 

 canthus, but none on clypeus. Horn of vertex replaced by a trans- 

 verse carina which has four small but noticeable tubercles, one at 

 each end of the carina and two slightly more than halfway toward 

 the median line. Pronotal modification of male with the pronounced 

 transverse carina deeply emarginate. Lateral limiting grooves 

 deep, lateral carinae large and elongate. In the female the transverse 



