NEW ABIERICAN BEES. 91 



Triepeolns denverensis, sp. nov. 

 ^ . Length about 13 mm., black, with the legs entirely bright 

 ferruginous, but the spurs of middle and hind legs black ; light mark- 

 ings pale ochreous, as in allied species ; wings only slightly darkened. 

 Head broad ; eyes (dry) pale reddish-grey ; face with dense appressed 

 white hair ; labrum black ; mandibles black except a little red about 

 the middle ; antennae black ; front and vertex coarsely and densely 

 punctured ; ocelli large, deep reddish ; viesothorax rather thinly covered 

 all over loith ochreous hair, the usual two bands very faintly suggested 

 by a greater density of the hair ; pleura densely imnctiired, covered 

 ivith hair, which becomes thinner below ; scutellum very strongly 

 bigibbous, lateral teeth strong, black, sharp, slightly curved inwards ; 

 tegulffi light ferruginous ; second s. m. much narrowed above, and 

 receiving the first r. n. in the middle ; abdomen with six broad entire 

 ochreous apical bands ; black band on first segment transverse, 

 rounded laterally, shorter than in T. occidentalis, connected with 

 base of segment by a narrow band ; band on second segment with a 

 large rounded anterior lobe on each side. Related to T. helianthi, 

 Robertson, but easily separated by the characters italicised. 



Hab. Denver, Colorado, at flowers of Peritoma serrulatum, 

 Aug. 11, 1908 {Mrs. C. Bennett). At the same flowers, at the 

 same time and place, Mrs. Bennett took Andrena argemonis, 

 Ckll. (both sexes), Megachile grindeliarum, Ckll., one female; 

 M. perihirta, Ckll., three males ; Melissodes obliqua, Say, one 

 male (a variety with green eyes, which has also been taken at 

 Boulder by Mr. S. A. Rohwer) ; and M. agilis, Cresson, var. b., 

 Ckll. (Univ. of Colorado Studies, 1907, p. 255). 



Megacliile perihirta has a large tubercle on the inner side of 

 the middle basitarsus near base, overlooked in the original 

 description. I am inclined to suspect that perihirta and grinde- 

 liarum are the sexes of one species. 



Ashmeadiella aridula, sp. nov. 



(? . Length about 5^ mm., black, including legs, with white 

 (not in the least yellowish) pubescence, and perfectly clear, iridescent 

 wings. Eyes green, black in front ; white hair dense on sides of face ; 

 mandibles black ; flagellum dull red beneath ; tegulse rufo-testaceous ; 

 apical teeth of abdomen tipped with red, the median ones much 

 longer than broad. Similar to A. cactorum, Ckll. (which occurs at 

 Florissant, Colorado), but distinguished by the colour of the tegulae, 

 antennge, and apical teeth of abdomen. It is perhaps only sub- 

 specifically distinct from cactorum. 



Hab. Rifle, Colorado, July 3, 1908 {S. A. Rohwer). 



I have referred to A. prosopidis, Ckll, two males from 

 Boulder, Colorado (May 26, S. A. Eohiver), and one from 

 Olympia, Washington State (July 1, Kincaid). They are not 

 precisely typical, and the Olympia one especially is rather too 

 large, with the wings not perfectly clear. It is probable that 

 with more material another species might be defined, but at 



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