448 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



V evtrolateral surfaces. — Body triangular, with surface lines 

 straight, evenly convex from side to side; surface smooth and im- 

 punctate; submarginal groove distinct and moderate beneath the 

 narrowly expanded external margin of the dorsal plate, terminating 

 at the fossa. Apex membranous beneath its chitinous and expanded 

 dorsal surface, finely setose; ventral plate distinctly defined apically. 

 Internal margins of the valves contiguous, fissure short and apical. 



Hahitat. — Arizona (AVilliams, May, Barber and Schwarz; South- 

 ern, coll., E, C. Van Dyke; Chiricahua Mountains, June, Hub- 

 bard and Schwarz; at base of Humphreys Peak, August, elevation 

 9,500 feet, F, H, Snow) ; New Mexico (F. H. Snow; Hubbard and 

 Schwarz; Coolidge; Magdalena, August, F. H. Snow, AVarren 

 Knaus) ; Colorado (Manitou, Packard). 



Number of specimens studied, 25, 



Type (female) in the LeConte collection. 



Type-locality. — New Mexico, 



Salient type-characters. — Head and thorax sparsely and finely 

 punctate, subdepressed, apex broadly emarginate, base truncate, 

 sides strongly rounded, posteriorly briefly sinuate, basal angles rec- 

 tangular, small and not prominent. Elytra obliquely declivous 

 behind and sinuately attenuate at apex, humeri obtuse, sides suddenly 

 inflexed, along the suture finely punctate, at the sides and apex 

 densely sculptured with small slightly elevated granules, anterior 

 femora subsifiuate (LeConte). 



Diagnostic characters. — Quickly recognized from marginata and 

 scahrioda by the flattened elytral disc. The prothoracic apex is gen- 

 erally slightly wider than the base, the sides are evenly arcuate 

 anteriorly and converge somcAvhat posteriorly, becoming slightly 

 sinuate in front of the basal angles, which are rectangular; disc 

 widest in front of the middle. 



In some specimens the elytra are very feebly flattened — in fact, 

 quite evenly l)ut not strongly convex — and the smaller of such ex- 

 amples greatly resemble the elongate form of snoicii found in Ari- 

 zona. The genital characters, must here be relied upon for their 

 separation. 



Plampenivis has heretofore been considered a Blapylis. It is the 

 nearest approach to Emhaphion that we possess; in fact, it could 

 with as much ])ropriety form a section in the latter genus as the one 

 in which it is now retained, and where it also must form a section 

 intermediate between Discogenia and EmhapMon. In genital char- 

 acters it is an EinJxipliion^ in facies an Eleodes. 



The constriction of the anterior tibia^ at base is not peculiar to the 

 genus Emhaphion. It is observed to a greater or less degree in the 

 different species of Blapylis; it is absent in the genus Eleodes., and 



