AMERICAN COLKOPTKRA. 159 



as the vertical diameter of the eye. First joint of antennae (fig. 23) moderately 

 stout; second short, angulate internally; third to eighth ramose, the processes 

 increasing in length from the third to the sixth joint, that of the latter being 

 about double that of the third joint, and snbequal in length to the ninth ; ninth 

 joint about as long as the five preceding united, the apical angle acute ; tenth 

 similar to, but slightly shorter than the ninth ; eleventh a little longer and very 

 slender. Prothorax three-fourths as long as wide, sides nearly straight and par- 

 allel as viewed from above; base truncate, feebly subsinuate each side; apex 

 moderately arcuate ; side margin obliterated anteriorly ; surface finely punctulate 

 and with scattered coarser punctures. Elytra equal in width to the prothorax 

 and a little more than three times as long ; finely scabrous apparently, but the 

 sculpture is almost perfectly concealed by the pubescence, and with faint traces 

 of longitudinal sulci. Presternum longer before the coxae than the longitudinal 

 diameter of the latter. Last ventral segment rather broadly evenly rounded at 

 apex. Length 6.5 mm. 



Tucson, Arizona (Hubbard and Schwarz). 



The type and only specimen is a male in the National Museum 

 collection. 



2. X. niacrnm n. sp. — Similar to the preceding, but with the elytra rela- 

 tively more elongate, four times as long as the prothorax and more distinctly 

 subsulcate. The head is subequal in width to the prothorax, the front a little 

 less than twice as wide as the vertical diameter of the eye; prothorax three- 

 fourths as long as wide, with distinctly arcuate sides. The auteunse (fig. 21) are 

 about two-fifths as long as the body, the three outer joints forming about half its 

 length. First joint stout, second much smaller but longer than wide, third 

 longer than the second and feebly prominent internally, fourth to eighth ser- 

 rate, the fourth and eighth evidently longer than wide, fifth to seventh as wide 

 as long; ninth equal in length to the three preceding together, tenth similar to 

 the ninth but just visibly shorter, eleventh slightly longer and narrower. As in 

 laticeps the presternum is very long before the coxse. Last ventral evenly 

 rounded at apex. Length 7.75 mm. 



California (Riverside). 



The unique type is a female taken by me at electric light in 

 June. 



3. X. cinereum Horn. — Similar in form and vestiture to desert'um. Head 

 a little narrower than the thorax. Joints 3-8 of antennae (fig. 24) pectinate, the 

 processes subequal in length to the joints. Elytra vaguely quadricostate. Last 

 ventral segment broadly feebly emarginate from side to side. Length 9 mm. 



This species was described from a unique taken in "Southwestern 

 Texas near the Rio Grande." It was referred by its author to 

 Ctenobium, doubtless because of the pectinate antennae, but the de- 

 scription, while somewhat unsatisfactory, pointed toward the present 

 genus, and inquiries kindly answered by Dr. Skinner and a subse- 

 quent examination of the type by myself verified this conclusion. 



TRANS. AM. ENT. SOC. XXXI. MAY, 1905. 



