410 Prof. T. B. A. Cockerell on 



median impressed line of mesothorax longer, extending as far 

 back as the level of the tegulse. 



Hab. Komeroville, April 29, 1 ? , at flowers of wild goose- 

 berry {W. Porter) ; Las Vegas (/?. Devine). 



It is possible that this is a distinct species, and it may even 

 prove to belong to 0. montana, Cress., of which only the 

 male has been described. 



Osniia (Melanosmia) nigrifrons^ Cresson, 

 var. suhausfralis^ nov. 



$ . — Smaller, length 10 millini. 



Anterior margin of clypeus with a distinct but broad and 

 shallow emargination, from the middle of which ])roceeds a 

 very fine raised line traversing the whole length of the clypeus, 

 but oidy visible in a favourable light ; apical tooth of 

 mandibles longer ; mesothorax with a smooth sparsely 'punc- 

 tured space on the middle of its disk ; sides of face tinged 

 with greenish (dark purple-blue in nigrifrons) ; mesothorax 

 black, with a faint green tinge posteriorly ; wings clearer. 



Ilab. Beiilah, July 'IQ, 1 ? [Wilmatte Porter). 



Probably a distinct species. Cresson, when describing 

 m'grifrons, seems to have confused this insect with it, as he 

 says " clypeus truncate or obtusely emarginate.'" 



Osmia {Melanosmia) ribijloris^ sp. n. 



?. — Length 11 millim. 



Thickly built (breadth of abdomen 4 millim.), dark shining 

 blue, including the legs, and tegulai more or less ; pubescence 

 black ; wings only faintly tinged with brownish, but the 

 upper half of the marginal cell occupied by a dark brown 

 streak ; mandibles very broad, without any patch of rufous 

 hairs, bidentate, the apical tooth quite long, the other small 

 but sharp, nearer to it than to the inner angle ; apex of 

 clypeus entire, shining, slightly rounded; punctures of front 

 and mesothorax strong, large, separate ; punctures of abdo- 

 men distinct but not dense ; ventral scopa all black ; spurs 

 black ; joints 2 to 4 of anterior tarsi inversely cordiforra. 



Hab. liomeroville, April 29, 1899, 2 ? , at flowers of wild 

 gooseberry ( Wilmatte Porter) ; Las Vegas, 1 ? [R. Devine), 



Allied to 0. Bruneri and cohaltina, but larger and much 

 more darkly coloured. The spurs of the hind tibise are small 

 and not hooked at the tip, thus resembling those of cobaltina 

 and differing from those of Bruneri. From several super- 

 ficially similar species it is distinguished by the blue legs. 



