248 AMERICAN COLEOPTERA. 



The type is apparently a male and was taken at " Mesilla, July 

 31, at light" by Prof. Cockerell. With it I associate a smaller 

 specimen from Yuma, Arizona, collected by Dr. Fenyes. No sexual 

 marks are evident. In the structure of the mentum this species is 

 approached hy pectoralis only, but in the latter the wedge is much 

 thicker at base than in gnatho, and its anterior face is concave from 

 side to side, while in the present species the concavity is from top to 

 bottom. In pectoralis, moreover, the prosternum is lobed in front, 

 and the basal joint of hind tarsus strongly modified. The mandi- 

 bles in gnatho are even more strongly produced than in mandibu- 

 laris, but are less strongly angulate externally. In the extremely 

 broad head it is approached by no other species at present known. 



Ochodteiis nimius n. sp. — Form, size and color o{ biarmatus. Mandibles 

 more prominent, their outer margin sinuate and obtusely angulate. Clypeus 

 somewhat thickened but without double margin, an acute tubercle at the middle 

 adjacent to the margin ; vertex devoid of transverse ridge. Mentum strongly 

 transverse, scarcely narrowed in front, anterior angles rounded, apex truncate, 

 surface nearly flat throughout. Prothorax a little less than twice as wide as 

 long, moderately closely granulate, impressed line distinct posteriorly. Elytra 

 very slightly more than twice as long as the prothorax, strial punctures rather 

 coarse, intervals nearly flat, irregularly punctate, sutural angle obtuse. Tibise 

 and tarsi nearly as in biarmatus. Length 5i mm. ; width 2i mm. 



"Mesilla, July 31, at light" (Cockerell). 



By its flat, strongly transverse mentum the present species must 

 be associated with striatus and sparsus. In striatiis there is no 

 frontal tubercle, and the vertex is transversely carinate, the color 

 darker and the elytral striae deeper. In sparsns the frontal tubercle 

 is much more posterior in position, being on the vertex instead of 

 adjacent to clypeal margin ; the angles of the labrum are more pro- 

 longed and the prothorax is shorter. 



dichi<:l,<»ivycha. 



The two following forms are closely related to backii and fnlglda 

 respectively, but differ so constantly in color through long series 

 that distinctive names are desirable, even though they ultimately 

 prove to be merely subspecies. 



D. testaceipenuis n. sp. — Black, elytra entirely testaceous in both sexes, 

 legs blackish in the male, pale in the female. In an occasional specimen the 

 suture is slightly dusky, and rarely there is discernible a faint greenish surface 

 lustre. Form, structure and sculpture virtually identical with backii. 



