184 PROCEEDINGS OF THE NATIONAL MUSEUM vol. km 



and entirely without setae. Epipleiiron and elytral margin each 

 bear a row of long setae. Along elytral margin and extending inward 

 no more than 0.5 mm. are a number of small setae; otherwise, elytra 

 and entire dorsal surface of thorax are bare. Mesosternal prominence 

 only slightly developed in front of middle coxae, not elevated above 

 plane of metasternum. Hair of underside moderately long and sparse. 



Head with tubercles of eye canthi and clypeus pronounced, sharply 

 upturned, Horn in center of vertex long, scarcely wider near base 

 than at tip, which is not bifid. Pronotal modification with pro- 

 nounced transverse carina deeply emarginate. Lateral limiting grooves 

 deep, lateral carinae large and elongate. 



Genital capsule blunt, lateral lobe about 1.3 times as long as wide. 

 Almost identical to that of B. pusillum except that the setae at the 

 tips of the lateral lobes are fewer and shorter than those of 5. 'pusillum. 



Allotype: female, length 8,5 mm., greatest width 6.1 mm. 



Markings similar to holotype except at pronotal modification where 

 there is only a trace of black along the transverse carina and in the 

 lateral limiting grooves. Tibiae brown edged with trace of black. 

 Coarse punctures of pronotum irregular and more numerous than 

 holotype, secondary punctures also more pronounced. Elytral striae 

 and punctures not showing significant variation, Foretibia armed 

 with seven teeth on outer margin. 



Head of allotype with suggestion of tubercle on eye canthus, but 

 none on clypeus. Horn of vertex replaced by a transverse 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 with the transverse carina slightly developed, 

 evenly arcuate. Lateral limiting grooves and lateral carinae barely 

 indicated, 



Holotype, male, St, Johns, Apache County, Ariz., May 28, 1931, 

 (from Barr collection) (USNM 61680), Allotype, female, Brewster 

 County, Tex,, August 24, Greene (USNM 61680), Paratypes, male, 

 Clovis, N, Mex,, Wickham, August (also paratype of pusillum Dawson 

 and McColloch) ; female. Mesa de la Eucnotada(?), 7,000 ft.. Sierra del 

 Carmen, Coahuila, Mexico, July 28, 1938, Baker; female, Valle de 

 Olivos, Chihuahua, Mexico, 5,500 ft,, July 20, 1947, D, Rockefeller 

 Expedition, Cazier; female, 5 miles east of Marathon, Brewster 

 County, Tex., 4,100 ft., Sept, 27, 1950, Gertsch and Cazier, Paratypes 

 in the collections of the American Museum of Natural History, O, L. 

 Cartwright, and the writer. 



Variation in the six specimens at hand is very slight. Size ranges 

 from 8.5 to 11 mm, in length, 6 to 7,2 mm. in greatest width. Pattern 

 is quite constant. Tibiae of the males are black, those of the females 



