158 ENTOMOLOGICAL SOCIETY 
Monilosmia canadensis Cresson. 
1888: Add. Fauna Ent. Can. Hym. p. 325, 329-330, c? p. 
466 (Osmia proxima). 
1896: Dalla Torre, Cat. Hym. v. X, p. 496 (O. proxima, 
Provancher references) . 
One cT specimen numbered 1164 and labelled 0. proxima. 
Provancher reports the species from "Ottawa (Guignard)." 
Centrosmia bucephala Cresson. 
1882: Le Naturaliste Canadien, v. XIII, p. 207, 208, n. 3, 
9 (O. lignicola). 
1883: Fauna Ent. Can. Hym. p. 707, 708, n. 2 (O. lignicola). 
1888: Add. Fauna Ent. Can. Hym. p. 324, 466 (O. ligni- 
cola); p. 325, 327-328, n. 13 (O. latitarsis). 
1896: Dolla Torre, Cat. Hym. v. X, p. 399 (O. latitarsis, 
Provancher references); p. 491, 9 (O. lignicola). 
The type of 0. lignicola is numbered 965 and Provancher 
records it from C\p Rouge, the species 0. latitarsis is numbered 
1168, and is also from Cap Rouge. 
Centrosmia tarsata Provancher. 
1888: Add. Fauna Ent. Can. Hym. p. 325, 328, n. 14, r d% 
p. 467 (Osmia tarsata). 
1896: Dalla Torre, Cat. Hym. v. X, p. 412 (Osmia tarsata). 
Length 9 mm. Rather slender, blue-black, abdomen shining blue, 
antennae deep brown, head with a greenish cast in some lights, margins 
of all the dorsal abdominal segments brownish, polished, and not punc- 
tured, first two pairs of legs blue-black (hind legs missing) 2d ventral 
segment reddish with a tendency in the center of the apex towards an 
upraised tooth; pubescence of face white and dense, dorsum of thorax 
with pubescence somewhat ochraceous (has been wet and is matted on 
the surface), first two dorsal abdominal segments, head and pleura with 
white pubescence; edges of segments with scarce pubescence ochraceous 
and black intermixed, pubescence of legs white on tibiae and ferrugi- 
nous on tarsi; antennae long rather slender, neither 3d nor 4th joint 
equals 1 + 2; mandibles polished, apical tooth very sharp; legs finely 
punctured, tarsi of middle legs deformed as in C. bucephala but are uioae 
slender and not so broadly deformed as in that species; outer spine of 
tibiae long and sharp, somewhat curved, spurs dark, one much longer 
than the other on hind legs; 6th dorsal segment minutely emarginate 
in the central margin and slightly sinuate at sides, yth segment notched 
sharply and deeply on apical margin, teeth pointed, 3d ventral showing 
in the form of lobes at the sides of and behind the 2d ventral which has 
a small upraised tooth on the center of its apical margin, 4th ventral 
with sides curved and tip broadly truncate; first submarginal cell nar- 
