174 Journal New York Entomological Society. [Voi. xxvi. 



This species is one of the largest in our fauna, only exceeded in 

 size b}- spinigcra and equaled by arizonica. Like the latter, it has a 

 prothorax which is very much broader at base than at apex, but has 

 an armature of a different type. The prothoracic incisure is more 

 nearly that of difficilis but the anterior angles of the incisure are 

 strongly reflexed along their posterior margins, whereas that char- 

 acter is lacking in the latter, and the posterior process is broader and 

 blunter. The general shape of deserticola is also different, very 

 broad behind, and the basal fovese are several times larger and the 

 disc deeply sulcate as against one that is unimpressed. 



Silis arizonica new species. 



Elongate, large, moderately shining, black with an entirely orange pro- 

 thorax. Head as broad as apex of prothorax, depressed between the eyes; 

 eyes prominent ; antennae filiform and reaching fully three fourths length of 

 body. Prothorax over one fourth broader at base than long and broader than 

 base of elytra, apex broadly rounded, sides in front almost straight and 

 widely diverging backwards, the posterior incisure a small fenestra bounded 

 in front by a hook-like process, the extension of the anterior angles, and 

 posteriorly by a broad and rounded process which extends directly outwards 

 from beneath the moderatly developed acute hind angles, this process having 

 at its middle a crest that extends forward and almost meets the anterior 

 process so as to partially close the incisure, the entire armature protruding 

 outwardly from the posterior angles, well beyond the line of the lateral mar- 

 gin, the posterior margin narrowly lobed, and the disc with small deep fovese 

 just within the lateral armature but otherwise without any sculpturing of 

 note. Elytra about 5.5 times as long as prothorax, wider posteriorly, coarsely, 

 closely punctate, and scabrous, with short, fine, and sparse ashen pubescence. 

 Beneath slightly shining in front and dull and rugose over abdomen. Length 

 7 mm., breadth 2.75 mm. (Plate IX, fig. 11.) 



Type in my own collection, captured at Prescott, Ariz., August, 

 1910, by Mr. J. August Kusche. In the National Museum series of 

 specimens are nine males and three females of the same species, all 

 collected in May and June, at Williams, Ariz., by Barber and 

 Schwarz. They are all somewhat smaller than the type, averaging 

 but 6 mm. in length. The females are slightly broader than their 

 mates, with finer and shorter antennae, and with the prothorax quite 

 transverse, almost twice as wide as long, the apex broadly rounded, 

 sinuate just before the anterior angles, the angles themselves ob- 

 liquely truncate, sides straight except just in front of posterior 

 angles where slightly sinuate, the posterior angles nearly rectangular, 

 and the posterior margin broadly lobed. 



