160 MEMOIRS ON THE COLEOPTERA 



three-fifths as wide as the prothorax, the eyes moderate as in the 

 two preceding; prothorax between two-fifths and one-half wider than 

 long, the parallel sides evenly and rather feebly arcuate, more so 

 and converging anteriorly; base feebly sinuate and transverse in 

 median half only, and not much more broadly as it is in robustus 

 and piceus, finely margined throughout; surface very convex, rapidly 

 declivous to the unusually .pronounced marginal gutter but scarcely 

 visibly and narrowly subexplanate about the broadly rounded hind 

 angles; basal foveae rather large and elongate, broadly impressed, 

 indefinite and wholly impunctate; elytra twice as long as the pro- 

 thorax and not wider, the apex very obtusely ogival, the sinus 

 barely traceable; striae rather fine, well impressed suturad, the 

 scutellar distinct, the foveae of the three series rather large and 

 impressed; under surface and legs piceous-black, the legs rufescent. 

 Length (9) 10.8 mm.; width 4.3 mm. Arizona (southern). 



pinguis Csy. 



Body not quite so stout and decidedly less convex, highly oplished 

 throughout, black, the upper surface with feeble violaceous lustre; 

 under surface and legs rather pale red'-brown, the antennae, palpi, 

 mandibles and labrum ferruginous; head rather small, but slightly 

 more than half as wide as the prothorax, the frontal impressions 

 very small, rounded and subperforate as usual; prothorax barely a 

 third wider than long, as wide as the elytra, widest slightly before 

 the middle, the sides subevenly and strongly arcuate throughout, 

 the apical sinus very shallow, much feebler than in the preceding 

 species; base finely margined, very feebly and evenly sinuate, 

 except near the sides, where it becomes feebly arcuate; surface 

 gradually declivous to the very fine marginal gutter, rather broadly 

 deplanate basally between the shallow and indefinite, minutely and 

 feebly punctulate foveae and the sides, having a few longitudinal 

 plicae medially at base as in crassicoHis; elytra barely more than 

 twice as long as the prothorax, not very obtusely ogival at tip, the 

 sinus virtually obsolete; striae not very fine, abrupt and deep, the 

 intervals nearly flat, the punctures of the series small; marginal 

 interval, extending more inwardly toward tip, finely and sparsely 

 punctate throughout, in a manner not evident in any of the preceding 

 species, the marginal series of large foveae widely interrupted as 

 usual; middle tibiae (cf 1 ) rather strongly arcuate and with the usual 

 modification, the tarsi as usual. Length (c?) 10.0 mm.; width 3.9 



mm. Arizona (near Benson), Dunn subviolaceus n. sp. 



8 Prothorax not much narrowed anteriorly, the apex subequal in width 



to the base, the basal angles very broadly rounded 9 



Prothorax distinctly and arcuately narrowed anteriorly, the apex much 

 narrower than the base, the basal angles more evident, rounded but 



less broadly so than ing 14 



9 Size moderate, seldom at all less than 7 mm. in length 10 



Size notably small, never so much as 7 mm. in length 13 



10 Elytral striae fine and feeble, the eighth very superficial and almost 

 obsolete basally, the marginal interval without trace of fine confused 

 punctures except apically. Body oblong, only moderately convex, 



