DIAPERmi NORTH OF MEXICO — TRIPLEHORN 395 



Pronotum transverse (pi. 6, fig. 53), sides strongly arcuate, especially from 

 middle to apex; apical angles rounded and deflected 14 



13. Outer elytral striae poorly defined for about }i to Ys the length of elytra at 



both base and apex; punctures shallowly impressed, rather widely and 

 irregularly spaced; color usually black; average size smaller (4.0-6.1 mm. 



in length) oregonense LeConte 



Outer elytral striae well defined, strongly punctured, almost attaining base 

 and complete at less than Yi the length of elytra at apex; color usually 

 brownish; average size larger (5.6-7.3 mm. in length). 



neglectiim, new species 



14. Sides of pronotum rather broadly expanded, somewhat crenulate with punc- 



tures conspicuously larger than those of disc; elytra broadly convex from 



side to side americanum Laporte and Brull6 



Sides of pronotum narrowly if at all expanded, evenly arcuate, punctures 

 shallowly impressed, poorly defined, subequal in size over entire pronotum; 

 elytra feebly convex to almost flat mexicanum Champion 



15. Clypeus large, well defined, trapezoidal; eyes sunken below surface of head 



medially; color dark reddish brown; known only from mountains of 



southern Arizona inquilinum Linell 



Clypeus moderate in size, poorly defined, transversely subquadrate; inner 

 margins of eyes raised above surface of head medially ; color usually black 

 or at least very dark 16 



16. Punctures of interstrial elytral intervals extremely minute and sparse; body 



brownish, feebly shining laevipes Haldeman 



Punctures of interstrial elytral intervals large and fairly dense; body black, 

 shining 17 



17. Ventral surface of pronotum smooth to feebly rugose; average size larger 



(5.0-6.0 mm.), robust, shining black. subcostatum Laporte and Brulle 



Ventral surface of pronotum coarsely and longitudinally wrinkled; size 



smaller (4.5-5.5 mm.), elongate, narrow, black with brassy or greenish 



reflections, shining picilabrum Melsheimer 



18. Outer elytral striae poorly defined for about Yi to Ys length of elytra at both 



base and apex oregonense LeConte 



Outer elytral striae well defined, strongly punctured, almost attaining base 

 and complete at less than }i the length of elytra at apex 19 



19. Outermost elytral striae approaching adjacent striae at base, leaving un- 



usually large humeral intervals; head densely, almost confluently, punc- 

 tured mieans Zimmerman 



Outermost elytral striae normally placed; head finely and sparsely punctulate. 



ruficolle Laporte and Brulle 



Platydema excavatum (Say) 



Plates 4 (Figs. 22, 2.3), 7 (Fig. 67) 



Diaperis excavate Say, 1824, p. 267. 



Platydema tuberculata Laporte and Brulle, 1831, p. 352. 



Platydema excavata (Say), Haldeman, 1848, p. 102. 



Platydema excavatum (Say), Horn, 1870, p. 381. — Champion, 1886, p. 184, pi. 8, 



fig. 11. 

 Platydema nigritum Motschoulsky, 1873, p. 470 [new synonymy]. 

 Platydema tiiberculatum (Laporte and Brulle), Chevrolat, 1878b, p. 210. 

 Platydema fratermnn Chevrolat, 1878b, p. 210. 



