106 S. A. ROHWER. 



not bounded by carinae at the sides. Legs rather slender; venation 

 as argentine and allied species. Abdomen shining, punctured with 

 strong, distinct, separated punctures; somewhat constricted between 

 the first and second segments. Color black; apices of the mandibles 

 and the palpi brownish; four anterior legs below the femore, base of 

 the hind tibia? and hind basi-tarsus brownish-orange. Wings hyaline, 

 iridescent; venation black. Except the face below the antennae the 

 insect is hardly pubescent. 



Habitat.— Florissant, Colorado, June 19, 190S (Prof. T. D. 

 A. Cockerel!). I take great pleasure in dedicating this distinct 

 little species to Prof. Cockerell. 



A very distinct species, easily recognized by the large 

 punctures of the abdomen and the small size. 



Didontus fraternus n. sp. 



Male. — Length 3.5 mm. Clypeus rather deeply semicircularly emar- 

 ginate, the angles sharp. Front closely, finely punctured; vertex, 

 occiput and cheeks with rather sparse, distinct punctures; frontal 

 impressed line present but not strong. Ocelli in a low triangle; the 

 distance between the two lateral ocelli a little greater than the distance 

 between one of them and the nearest eye margin. Antenna? robust; 

 the third joint shorter and smaller than the fourth, apical joint longer 

 than the preceeding one, but not nearly as long as 11 and 12. Dor- 

 sulum shining, sparsely punctured, two parallel grooves in the middle. 

 Mesopleurae granular, somewhat striated. Scutellum 'convex, the 

 suture between it and the dorsulum, and it and the postscutellum deep; 

 the scutellum shining, impressed in the middle, not depressed at the 

 sides. Metanotum rugose with an indication of a channel; meta- 

 pleurse with strong irregular striae; posterior face not margined laterally 

 by carinae; with a triangular fovea in the middle above. Legs not 

 very robust; venation as in argentine?. Abdomen shining, impunctate, 

 not constricted between the segments. Color black; mandibles except 

 the piceous apices bright lemon yellow; tegulas and tubercles pallid; 

 flagellum beneath orange-color; legs below the knees reddish-yellow. 

 Face with silvery pile. Wings slightly dusky hyaline, iridescent; 

 venation black. 



Habitat. — Florissant, Colo., June 23, 1907 (S. A. Rohwer). 



This species is related to crassicomus Vier. in the robust 

 antennae, but differs in the color of the legs, and the antennas 

 are not serrate. 



Diodontus neomexicanus n sp. 



Male. — Length 2.5 mm. Labrum shallowly emarginate. Clypeus 

 with a truncate tooth. Front with distinct separate punctures; 

 vertex, occiput and cheeks more sparsely punctured. Front seen 



