Sept.-Dec, I9i8.] VaN DyKE : REVIEW OF GeNUS SiLIS. 175 



This species is somewhat suggestive of deserticola, particularly 

 as regards the greater breadth of the prothorax posteriorly, but its 

 armature is much like that seen in fenestrata. It is a species of the 

 highlands of northern Arizona, a region where S. difficilis Lee. is 

 also to be found. 



Silis fenestrata new species. 



Elongate, but slightly shining, black with disc of prothorax orange. 

 Head as broad as apex of prothorax, depressed between the eyes ; eyes mod- 

 erately prominent and well separated; antennae reaching over three fourths 

 the length of body, quite filiform, the median joints not serrate; prothorax 

 about one fourth broader than long, as broad as base of elytra, apex broadly 

 rounded, sides in front almost straight, divergent posteriorly, the posterior 

 incisure small and almost entirely closed, the acute anterior angle bounding 

 it extending obliquely backwards, overlapping, and partially locking with the 

 hook-like process of the posterior appendage, this latter projecting outwardly 

 from the base itself, the outer part of the armature not extending beyond the 

 normal lateral margin, the base lobed, the disc feebly convex with a poorly 

 defined longitudinal' impression and rather deep basal fovese, and the anterior 

 and posterior margins moderately reflexed. Elytra four and a half times 

 as long as prothorax, widest one third distant from apex, the disc rather 

 coarsely and closely punctured, somewhat rugose and dull, and rather finely, 

 sparsely clothed with cinereous pile as usual. Beneath shining in front and 

 dull rugose over abdomen. Length 5.5 mm., breadth 2 mm. (Plate IX, 

 fig. 10.) 



Type, a unique male in my collection, given to me by Mr. J. C. 

 Bridwell, who captured it on Mt. San Jacinto, southern California, 

 July, 19 1 2. 



It is a species which has its closest relative in arizonica but its 

 non-protuberant armature will readily separate it from that. 



Silis nigerrima Schaef. 



Silis nigerrima Schaef., Journ. N. Y. Ent. Soc, Vol. XVI (1908), p. 66. 



This species forms, with the three following, a group which while 

 having the general facies, type of antennae, and so forth, character- 

 istio of the species which precede, yet shares with the succeeding 

 three and more typical members of the subgenus Ditemnus their most 

 important features, and thus serves as a connecting link between 

 the two groups. It is entirely black and the most distinctly charac- 

 terized of the three all black forms found within our territory. So 

 far, it has only been found in the mountains of southern Arizona, 

 such as the Huachuca and at Camp Grant in the Pinaleno Mountains. 

 (Plate IX, fig. 12.) 



