June, '08] ENTOMOLOGICAL NEWS. < 257 



posterior face; convexities finely, longitudinally striated; middle fur- 

 row triangularly foveolate on posterior face above; posterior face and 

 sides striato-punctate ; striae stronger; middle tibiae with apical spur; 

 femora rather more robust than usual; transverse cubitus received a lit- 

 tle before middle of radial cell ; abdomen shining, impunctate, pygidium 

 triangular, rather sharp at apex, but not excavated, with a few large 

 punctures. Color black; scape in front, mandibles except apex, 

 tubercles, tips of anterior femora, anterior tibiae, middle tibiae except a 

 black spot, base of posterior tibiae, basal joint of middle and posterior 

 tarsi yellowish; anterior tarsi ferruginous; clypeus, cheeks, thorax at 

 sides and beneath with silvery pubescence, wings clear hyaline, irides- 

 cent ; nervures and stigma dark brown. 



Habitat Jim Creek, Boulder Co., Colo., Sept. 7, 1907 (S. 

 A. Rohwer), fls. Eriogonum effnsum, Transition Zone. 



Accompanied at flower by Crabro errans Fox, Prosopsis spp., 

 Odynerns spp. 



In Fox's table runs between propinquus Fox (Texas) and 

 minimus Pack. (Eastern States) but there is no median promi- 

 ence on the clypeus, and it differs in other characters. 



Rhopalum modestum n. sp. 



$ . Length $ l / 2 mm. ; anterior wing 4 mm. Head smooth, shin- 

 ing, impunctate; around each lateral ocelli is a depressed area; front 

 slightly broken in middle by a line; facial basin rather narrow, shin- 

 ing ; antennae rather slender, pedicellum with tooth beneath, first 

 flagellular joint emarginate, second produced beneath, remaining simple, 

 pale at base ; clypeus strongly produced medially, sides of this pro- 

 jection with small teeth, in middle there is a rounded tooth; pronotum 

 rounded ; dorsulum with very fine punctures ; meso-pleurae almost im- 

 punctate, suture almost wanting; suture of metathorax strong; meta- 

 thorax shining; ridge on sides of posterior face; posterior four tro- 

 chanters elongate; femora robust, especially the anterior pair; pos- 

 terior tibiae enlarged at apex ; venation normal for genus ; abdomen 

 as usual in this genus. Color shining black; clypeus somewhat and 

 antennae piceous ; scape beneath, tubercles, apical half of coxae, tro- 

 chanters, apex of four anterior femora, their tibiae except a black spot 

 within, anterior four tarsi, base of posterior tibiae yellow; tegula?, apex 

 of posterior tibiae, apex of abdomen brownish-red; clypeus and lower 

 inner orbits with silvery pubescence; wings clear hyaline; iridescent; 

 nervures dark brown. 



Habitat Boulder, Colo., May 30, 1906 (T. D. A. Cockerell). 



Rhopalum Kby. group pcdiccllatus Fox. This agrees 

 exactly with this genus. The following table will separate the 

 American species of this genus in the male sex. 



