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



ventral and sides of third with fringes of long black hair ; 

 emargination of third with short whitish hair. 



In the Florissant table runs to O.faceia, but differs by the 

 non-moniliform antennae and other characters. In the 

 Boulder County table runs to 0. viridior, but is much 

 smaller and of a different colour. Disregarding the few 

 black hairs at sides of vertex, it runs to 0. Wheeleri, which 

 it closely resembles ; but it is easily known from Wheeleri 

 by the black hair at sides of metathorax, structure of apex of 

 abdomen, &c. The first two small joints of the middle tarsi 

 are swollen, as in 0. universitatis and integrella : universitatis 

 has the hair on the sides of the metathorax light and the 

 abdomen greenish ; integrella is considerably larger than 

 amala and the abdomen is of a very different colour. In 

 size and the colour of the abdomen 0. amala resembles 

 0. color adella. 



Hah. Florissant, Colorado, June 30, 1907 {S.A. Rohwer). 



Osmia mertensia;, sp. n. 



S . — Length about 8 mm. 



Head and thorax green, glittering; abdomen deep blue-green, 

 very shiny, the hind margins of the segments concolorous ; 

 legs strongly tinged with green ; hair of head and thorax 

 long and white; no dark hairs on thorax, but a few long 

 dark hairs on anterior part of cheeks ; hair of legs pale, with 

 some black intermixed ; hair of hind femora partly pale and 

 partly dark ; clypeus normal, covered with a dense brush of 

 hair ; flagellum only moderately long, not at all moniliform, 

 ferruginous beneath ; wings strongly dusky ; tarsi normal. 

 Abdomen with short black hair beyond second segment ; 

 sixth notched ; seventh bidentate ; venter normal. 



In the Florissant table runs to 0. Wheeleri, of which it 

 may possibly be a variety, but the antennae are differently 

 coloured, and the sixth abdominal segment is only feebly 

 notched, and does not bulge at the sides as it does in 

 Wheeleri. In the Boulder County table it runs to 0. aprilina, 

 but that has the pubescence, antennae, &c. quite different. 

 The vertex of mertensice not only shows some black hairs at 

 the sides, but there are black hairs about the ocelli. 



Hah. Florissant, Colorado, at flowers of Mertensia lanceo- 

 lata, June 19, 1907 (S. A. Rohioer). 



Osmia enena, sp. n.* 

 (J . — Length about 9 mm. 



Dark blue. Superficially similar to 0. mertensice, but 

 differing thus : antennas considerably longer, the flagellum 



* Enena, a Malay word meaning small. 



