446 Mr. T. D. A. Cockerell — Descriptions and 



form very slender, with the abdomen long and parallel-sided; 

 pubescence white throughout ; scape green ; flagellum long 

 and slender, ferruginous, darkened above ; apical dorsal seg- 

 ment concave above, its apex broadly snout-like, not at all 

 notched ; a small spine on each side of the penultimate 

 segment. 



Var. a. — Hind margins of abdominal segments narrowly 

 brilliant purple ; vertex suffusedly crimson and golden. One 

 specimen, July 6. 



By the narrow form and the structure of the abdomen, 

 this species is allied to Monumetha^ but tiie antennae are 

 normal for Osmia. 



Osmla pentstemonis, Ckll., 1906. 



Var. a. ? . — Light hair of tliorax strongly yellowisli. 

 Florissant, Colorado, at flowers oi Besseya plantaginea, June 1, 

 1907 (6'. A. Rohioer). 



Osmia pliysaria-^ sp. n. 



^ . — Length about 8j mm. 



Blue-green, shining; ])ead and thorax with copious long 

 liair, which is faintly yelh)wish dorsally, but otherwise white, 

 with no dark hairs intermi.red ; flagellum dark reddish and 

 very stronyly crenuJate beneath ; legs black, not at all metallic, 

 their hair white, last tarsal joint ferruginous; form of tarsi 

 normal ; tegulse piceous with a large green spot. Wings 

 hyaline, a little dusky, but not at all reddish ; b. n. meeting 

 t.-m. Abdomen subglobose, with abundant dull white hair, 

 which tends to form marginal bands ; sixth dorsal segment 

 firjectly entire ; seventh bidentate ; first ventral entire. 



]n the Florissant table of Osmia (Bull. Am. Mus. Nat. 

 Hist. 1906) this runs to 0. faceta, but that is veiy different 

 by the black hair on the abdomen, hi the Boulder County 

 table (Univ. of Colo. Studies, 1907) it runs to 0. proxima^ 

 but that is a smaller and otherwise different species. The 

 antennae suggest 0. chJorops, but the flagellum is shorter, and 

 the hind tarsi are different; the wangs also are diff'erently 

 coloured, 



llab. Florissant, Colorado, at flowers of Physavia^ June 1, 

 1907 (6'. .4. Rohwer). 



Osmia seneciophila, sp. n. 



(^ . — Length 9 mm. 



Head and thorax very dark dull blue, a little greenish on 

 scutellum ; abdomen shining indigo-blue, closely punctured ; 

 hair of head and thorax white ; hair of cheeks white, except 

 just behind the eyes, where it is long and black; extreme 

 sides of vertex with a few black hairs, and even a very few 



