THE CANADIAN ENTOMOLOGIST. 357 



it is doubtless of the Monilosmia type. Osmia chlorops Ckll. and 

 Titus, which occurs in the same locaHties as densa (e.g., at Floris- 

 sant), and like it visits Pentstemon, is doubtless the male of densa. 

 It is hardly different from the Milwaukee "simillima.'' 



0. novaescotiae, compared with a number of species w^hich have 

 white hair on the pleura in the female, differs (1) from alholateralis 

 by the deep blue (not green) abdomen, total absence of black hair 

 on vertex, etc. ; (2) from coloradella by the non-metallic legs, abdo- 

 men seen from above showing black hair projecting at sides, etc.; 



(3) from densa by absence of black hair on front, blue abdomen, etc. ; 



(4) from dubia by the shining middle of mesothorax, largely pale 

 hair on legs, and blue abdomen; (5) horn faceta by the simple cly- 

 peus, etc.; (6) iromfelti by the much smaller size, dorsal abdominal 

 segments sculptured almost to apex; (7) from melanotricha by the 

 blue, more densely sculptured abdomen, and absence of black 

 hair on vertex; (8) from pentstemoyiis by absence of coarse black 

 hair on head and vertex; (9) from phaceliae by absence of black 

 hair on vertex and scutellum, and blue abdomen. 



Osmia suharctica n. sp. — 9 , Length, nearly 1}/2 mm. ; dark steel- 

 blue, the femora and tibiae metallic, the tarsi piceous; head rather 

 large, densely punctured, clypeus and sides of face a fine dark blue; 

 clypeal margin entire; mandibles tridentate; flagellum obscure ferru- 

 ginous beneath ; hair of clypeus black, but of sides of face white ; hair 

 of vertex pale, but front with a slight intermixture of fuscous hairs; 

 hair of thorax entirely rather dull white; mesothorax and scutellum 

 closely punctured , but shining ; area of metathorax dull and granular ; 

 tegulae dark rufopiceous, blue in front ; wings dusky hyaline ; b.n. ex- 

 actly meeting t.c. ; hair of legs largely black, brown-black on inner 

 side of tarsi; abdomen moderately vshining, with shallow sculpture, 

 dorsally with extremely short and scanty hair, white at sides; 

 no hair-bands; ventral scopa black, w^ith coppery tints. 



Hab. — Hudson's Bay, 44-17. Closely related to 0. pentste- 

 monis Ckll., but separated by the absence of dark hairs on thorax 

 above, and the less shining abdomen. It is perhaps not more than 

 a subspecies of pentstemonis, but I have a series of the latter, all 

 looking different from siiharctiCa. 0. suharctica, compared with 

 other species having white hair on the pleura of the female, differs 

 thus: (1) From alboJateralis by the metallic legs, much smaller 

 size, etc ; (2) from coloradella by dark hair of middle of face, etc. ; 

 (3) from densa by the metallic legs and much smaller size ; (4) from 

 duhia by the metallic legs, etc. ; (5) from faceta by the much smaller 

 size, simple clypeus, etc. ; (6) from/e//i by the much smaller size and 

 metallic legs; (7) from melanotricha by the metallic legs, absence of 

 long black hair in sublateral region of abdomen, and narrower head ; 



