TlcconJs of Bites, 229 



basal middle of second very ^^ll()rt and white ; .scoi)a black; 

 hind s|)nrs curved at end. 



Allied to O. Imvis, Cresson, hut easily known from that 

 by the stnjuf; admixture of bhu^k hair on the thorax above. 

 It may also be compared with 0. /lit/rifruiis, Cresson, but 

 that is very much larj^^er. 



Jfa/j. Houhlcr, Colorado, June 1:2, 11)05 {Wilnuittc P. 

 Cockerel/) . 



Osmia color u del I a, sp. n. 



$ . — Tjen<:fth nearly 9 mm. 



Steel-blue, the head and tliorax very densely punctured, 

 the abdomen shining ; hair of head and thorax loiii^ and 

 rather copious, entirely white, with no yellow tinge ; anterior 

 edge of clypeus straight, with a suggestion of crenulation, 

 but no teeth ; tufts of hair under auterior edge tipped with 

 orange ; mandibles with the usual two large teeth and no 

 patch of yellowish pubescence (such as is seen m facetu) ; 

 middle of face somewhat greenish ; antennae black ; no 

 smooth spots on mesothorax mesad of teguUc (such as are 

 seen in atriveidris) ; area of metathorax minutely roughened 

 and dull, except tlic broad hind margin, which is shining ; 

 tegulae greenish in front. Wings hyaline, clouded on. apical 

 margin ; b. n. meeting t,-c. ; first r. n. only a little more 

 distant from base of second s.m. than second is from its 

 end. Legs black, with greenish-blue tints, which are quite 

 conspicuous ; their pubescence white ; hind spurs curved at 

 end. Abdomen convex, well-punctured, its dorsal hair 

 entirely white, and forming rather indistinct bands on the 

 apices of the segments, only seen when the abdomen is viewed 

 from the side ; ventral scopa black. 



Very close to 0. atriventris, Cresson, but not the same. 



llab. liouldcr, Colorado, June -1-, 1903 ( W. P. Cockerel/). 



Mega chile opuntiaruni, sp. u. 



? . — Length 13 mm. 



Belongs to M('(jach\/e, s. str., as defined by Robertson, and 

 is exceedingly like M. c/eoiais, Ckll., from which it (lifters as 

 follows : — clypeus very shiny, the punctures in the middle very 

 sparse, small, and weak ; apical border of mandibles reddened; 

 hair of top of head white, the vertex with only a few incon- 

 spicuous fuscous hairs; hair of thorax above white, the disk 

 of mcsuthorax posteriorly with scattered dark hairs; disk of 

 mesothorax somewhat shiny, the punctures rather smaller 

 and not so coarse ; tegnhe reddened on outt-r side ; scutellum 

 shining, the small punctures quite sparse in the middle ; 



