230 MEMOIRS ON THE COLEOPTERA 



unmodified in any way by impressions or tubercles, being perfectly 

 simple as in the Cyclocephalids. I have not been able to determine 

 whether stridulating organs are present or not. There is but a 

 single described species as follows: 



Male oblong, strongly convex, gradually feebly inflated behind, casta- 

 neous to blackish, the anterior parts black, strongly shining; head 

 evidently more than a third as wide as the prothorax, very coarsely 

 punctato-rugose, the transverse ridge entire, gradually more ele- 

 vated medially, very precipitous behind but forming the sloping 

 clypeus in front, the slope continuing to the moderately upturned 

 and narrowly truncate tip, the clypeus short, strongly trapezoidal, 

 with slightly sinuate sides; antennae moderate, thick, the club re- 

 latively very small, scarcely longer than thick; prothorax nearly 

 three-fourths wider than long, the sides rather strongly, evenly 

 rounded, more convergent apically than basally, the base broadly 

 arcuate medially, not impressed near each side and with a thick 

 entire marginal bead; punctures coarse apically, very coarse and 

 confluent antero-laterad, elsewhere very sparse though still moder- 

 ately coarse and somewhat deep; scutellum as wide as long, extremely 

 obtusely ogival, with rounded sides and some scattered coarse 

 punctures; elytra a sixth longer than wide, not abruptly rounded 

 behind, widest behind the middle and there fully two-fifths wider 

 than the prothorax, fully two and one-half times as long, each with 

 three discal and one sublateral double series of very small and feeble 

 punctures, the two inner costulae slightly convex, all the sculpture 

 extremely fine, feeble and subobsolete, except on the broad second 

 interval, where the confused punctures are sparse, coarse, moder- 

 ately impressed and subrugose; pygidium evenly and strongly convex, 

 two-thirds as wide as the elytra, two-thirds wider than long, strongly 

 arcuate above, smooth, with fine dense punctulation at the lateral 

 ends and a few coarse punctures scattered near the base; propygidium 

 everywhere finely but deeply, densely and rugulosely punctate, the 

 suture deep and free throughout. Female smaller and rather 

 narrower than the male, polished, black in color, castaneous beneath, 

 the sculpture of the same character as in the male but everywhere 

 less accentuated and, on the elytra, almost obsolete; basal bead of 

 the pronotum broadly obsolete medially; scutellum more rugose at 

 base; pygidium two and one-half times as wide as long, feebly arcuate 

 above, with close-set and strong punctures everywhere except on the 

 transverse, prominently convex surface which slopes rather abruptly 

 apically from just below the middle of the length, the apical margin 

 finely, rather abruptly reflexed, the surface nowhere pubescent; 

 last ventral long, broadly subangulate at apex. Length (cf) 24.8, 

 (9) 21. o mm.; width (cT) 13.2, (9) 11.5 mm. Arizona (Tucson), 

 Wickham dunnianus Rivers 



An extended account of this genus was given by Mr. Rivers 

 (Bull. Cal. Acad., 2d ser., I, p. 100), based upon El Paso specimens, 



