:358 THE CANADIAN ENTOMOLOGIST. 



(8) from phaceliœ by the metallic legs, absence of black hair on 

 scutellum, and narrower head. 



Osmia atriventris Cresson. — cf. Ent. Club, 44-12. The ac- 

 cession number is the same as that of O. novœscotiœ, but there is 

 no locality label. 



Osmia ter sula, n. sp. — cT, Length about 83^ mm.; head and 

 thorax densely granular-punctate, very dark green, with abundant 

 long, wholly pale hair, slightly creamy-tinted on thorax above and 

 head; mandibles stout, strongly curved, bidentate, the teeth sub- 

 equal; face narrowing below; antennae entirely dark, moderately 

 long, not moniliform; area of metathorax blue-black, dull, granular; 

 tegulae piceous, punctured; wings dusky hyaline, b. n. meeting t.m.; 

 second s.m. unusually long and low; legs brown-black, the femora 

 and tibiae not metallic, their hair long and pale, yellowish on inner 

 side of tarsi; middle tarsi simple; hind basitarsi toothed; abdomen 

 shining, very dark blue-green, the hind margins of the segments ob- 

 scurely reddish; basal segment with long, pale hair; apical segments 

 with conspicuous, long hair, wholly pale; middle segments almost 

 hairless; no hair bands; venter with pale hair; margin of sixth seg- 

 ment with a shallow notch; seventh emarginate, hardly bidentate; 

 first ventral entire; third ventral with an orange tuft or pencil of 

 hair on each side of emargination. 



Hab. — Hudson's Bay, 44-17. Distinguished especially by 

 its dark color and toothed hind basitarsus. In Schmiedeknecht's 

 table of European species it runs close to O.panzeri, but differs en- 

 tirely in the antennae and the pubescence. It may also be compared 

 with 0. angustula, which is smaller, with quite different pubescence. 

 In our fauna there is closer resemblance to several species of the 

 Rocky Mountains. The following table separates it from some of 

 these: 



Hair of vertex partly dark 1 



Hair of vertex wholly pale • • 2 



1. Scutellum with a median smooth line; teeth of mandibles 



subequal pulsatillœ Ckll. 



Scutellum without a smooth line; apical tooth of mandibles 

 very long vallicola CklL 



2. Abdomen shining blue; seventh segment very strongly bi- 



dentate wheeleri Ckll. 



Abdomen dark greenish; seventh segment 



emarginate tersula Ckll. 



From 0. tersula, O. amala Ckll. differs at once by the bright 

 blue abdomen and much larger antennae; 0. enena Ckll. by the blue 

 abdomen, strongly bidentate seventh abdominal segment, and 

 broader face ; 0. seneciophila, by the abundant black hair on apical 

 part of abdomen. 



