454 PROCEEDINGS OF THE NATIONAL MUSEUM vol. i04 



the sides and the smooth, shining occiput. Clypeus moderately 

 deeply, angularly emarginate at middle, a sharp triangular tooth each 

 side of emargination, sides arcuate, finely reflexed; genea obtuse, 

 shining, with a small deep pit in front of the eye, not fimbriate. 

 Pronotum convex, width 1.3, length 0.8, anterior angles rounded, 

 posterior angles very broadly rounded, sides finely crenate, fimbriate 

 with moderately long, very fine, curving hairs, finely margined ; with- 

 out transverse grooves, surface smooth and shining but with inter- 

 mixed extremely fine and rather widely, irregularly scattered, moderate 

 punctures over basal two-thirds of discal area, smooth laterally beyond 

 fovea. Elytra convex, margined basally, width 1.6 mm., length 2.0 

 mm., humeri finely dentate, sides arcuate, fimbriate with extremely 

 short, fine, inconspicuous fimbriae; striae deep, fine punctures crenat- 

 ing the sides of the slightly convex intervals. Metasternum smooth 

 and shining except for a small scabrous area at extreme sides, midline 

 deep, terminating suddenly at each end. Abdominal segments 

 convex, smooth and shining, a few scattered small tubercles outward 

 near sides, finely crenate in front, the terminal segment more widely 

 and deeply so at middle. Pygidium smooth, shining, but surface 

 somewhat uneven. Anterior femur with four or five setae in anterior 

 marginal line, posterior face with scattered setigerous punctures. 

 Middle and hind femurs smooth, shining, with fringe hairs along 

 anterior edge and four or five long hairs along extreme posterior edge, 

 usual curving row near knee represented by only one or two short, 

 fine hairs, posterior marginal line absent; posterior femur about one- 

 third wider than middle femur. Posterior tibia twice as long as its 

 apical width; long spur and first tarsal joint about equal in length, 

 tarsus very slightly longer than apical width of tibia. Length 3.2 

 mm., width 1.6 mm. 



Type: USNM 62491. 



Type locality: San Bias, Nayarit, Mexico. 



Specimens examined: Holotype and 11 paratypes collected at San 

 Bias, Nayarit, Mexico, Sept. 17-21, 1953, at light, by Borys Malkin. 

 Paratypes are in collections of Borys Malkin and U. S. National 

 Museum. 



Remarks: The typical series shows considerable variation in color, 

 ranging from light castaneous to rufopiceous. The elytra become 

 darker first, followed by the pronotum, with the head last. Psam- 

 modius formosus superficially resembles bidens but is shorter in length, 

 the elytra are fimbriate with very short inconspicuous hairs, and the 

 head has fine close granules above the front. 



Psammodius chipiririi, new species 



Holotype oblong, convex, sides subparallel, shining, piceous with 

 legs, anterior margin of clypeus and pronotum rufopiceous. Anten- 



