Sept.-Dec, I9i8.] VaN DykE : REVIEW OF GeNUS SilIS. 177 



angles as in nigcrrima. The males have the elytra laterally mar- 

 gined with yellow. The prothorax of the female is almost squarely 

 truncate in front, broadly rounded posteriorly, and with sides almost 

 straight but divergent to the obliquely truncated hind angles, the 

 elytra distinctly rugose whereas they are not so in the males, and 

 with both lateral and sutural margins yellow. It is found in Texas, 

 specimens from Dimmit Co. and Brownsville having been seen. 

 The Mexican, 6\ dilaccrata Gorh. is its closest relative and is in fact 

 but a mere variety of this as comparison with an authoritatively 

 determined specimen has shown. The latter has only the black 

 median longitudinal pronotal stripe to separate it. In the LeConte 

 collection the specimen bearing the label is undoubtedly not the type. 

 In fact it is not fossigcr at all but the following, tricornis. The type 

 from Texas is probably in the Horn collection. LeConte retained an 

 Arizona specimen for his collection but did not carefully compare it 

 with the Texas type.^ 



Silis tricornis new species. 



Small, short, but slightly shining, black with prothorax orange, slightly 

 maculated in front and behind with black. Head as broad as apex of pro- 

 thorax and depressed between the eyes. Prothorax about one third broader 

 than long, apex straight and not reflexed, sides diverging from apex for an- 

 terior third, then merging with the lateral armature which consists of a broad 

 horn-like process extending backwards from in front of the middle and a 

 broad plate extending outwardly from behind it terminating in an anterior 

 tooth and a posterior spine, the opening between the two processes narrow, 

 the basal angles small, very acute, and somewhat posterior to the armature, 

 the base truncately lobed, the disc with a broad, deep fossa at middle, and 

 transverse sulcus close to basal margin. Elytra slightly more than four times 

 length of prothorax, somewhat wider posteriorly, broadly rounded apically, 

 distinctly margined, the disc scabrous and with a sparse yellowish pile. Be- 

 neath opaque and finely rugose. Length 3.75 mm., breadth 1.5 mm. 



Type, a unique in the National Museum collection, taken at Hot 

 Springs, forty-five miles north-northwest of Phoenix, Ariz., June 22, 

 by Barber and Schwarz, and marked Type, Cat. no. 21696, Hot 

 Springs, Ariz. (Schwarz and Barber). The specimen is somewhat 

 mutilated, the antennse having been lost. A second specimen is in 

 the LeConte collection, labeled as fossiger. 



1 Upon examining the Horn Collection, I iind that niy surmise is correct. 

 The Texas specimen upon which the description is based is there. Tt is there- 

 fore the true type. With it are five other specimens, all from Arizona, and all 

 like the LeConte specimen. 



