190 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



circular postmedian spot. Spot is entirely in posterior third of elytra 

 and is separated from lateral margin and vaguely separated at the third 

 elytral interval from the expanded sutural stripe. The spot is 

 separated by five or six striae from the lateral elytral margins, which 

 are without black marldngs. Ventral surfaces yellowish brown. 

 Outer margins of foretibia edged with brownish black. Vertex 

 coarsely, sparsely punctured; punctures of clypeus generally regular 

 and dense. Pronotum, coarsely, moderately, irregularly punctate; 

 lateral portions more finely, closely punctured, more so anteriorly. 

 Minute secondary punctures evenly distributed over pronotum. 

 Declivity of pronotal modification with small coarse punctures only 

 in lower half. Pronotum with numerous, very small secondary 

 punctures. Secondary punctures on scutellum about twice the 

 diameter of those on the pronotum. Second elytral striae entirely 

 lacking. Fifth and eighth striae indicated only by a line of very 

 small punctures. Punctures in striae not sharply delimited, generally 

 scattered over the elytra are a few long erect yellow hairs. Epipleuron 

 and elytral margin each bear a row of long setae. Sides of the elytra 

 are almost parallel for approximately half their length, making this 

 species in proportion appear more elongate than other species of 

 Bolbocerosoma. Foretibia armed with eight teeth on outer margin. 

 Mesosternal prominence poorly developed in front of middle coxae, 

 only slightly elevated above plane of metasternum. Hair of under- 

 side long and moderately dense. 



Head with tubercles of eye canthi and clypeus pronounced, sharply 

 upturned. Horn in center of vertex long, slimly conical, not bifid at 

 tip. Pronotal modification with pronounced transverse carina deeply 

 emarginate. Lateral limiting grooves deep, lateral carinae large and 

 elongate. 



Genital capsule of male blunt, falling into the same general group 

 as pusillum, lepidissimum, etc., but much more elongate. The lateral 

 lobes of the capsule are about 1.8 times as long as wide (pi. 3, fig. 5). 



Female is unknown. 



Holotype, male, Chisos Mountains, Big Bend, Tex., July 8, 1946, 

 Van Dyke Collection (CAS). 



This species can be distinguished by its slightly elongate form, by 

 the rather elongate blunt genital capsule of the male (pi. 3, fig. 5), by 

 the scattered long erect yellow hairs on the elytra, by the thin vague 

 black band on the posterior pronotal margin, and by the vague 

 circular brownish black spot confined to the posterior third of the 

 elytron and separated from the sutural stripe. 



Additional material will probably indicate that the holotype is 

 rather poorly marked, as the black circular spot may in other specimens 

 be confluent with the sutural stripe. 



