222 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.42. 



major Robertson, 1902. Illinois (Robertson). Tab. 4. 



Near to atnvenlris, but larger; female 11, male 10 mm. 

 malina Cockerell, 1909. Near Boulder or Loveland, Colorado (C. De Voss). 



Superficially like 0. wilmattx, but thorax above with much more black hair, ocelli 

 larger, face with tufts of white hair. 

 *mandibularis Cresson, 1878. Colorado (Morrison). 



Female with nodose process on mandibles, 

 marginipennis Cresson, 1878. Colorado (Morrison). 



"May be the male either of longula or juxta" (Cresson). 

 mania Cresson, 1878. California (Henry Edwards). 



Entirely deep black, with black hair, 

 megacephala Cresson, 1864. Rocky Mountains, Colorado. 



Resembles 0. bucephala. 

 melanotricha Lovell and Cockerell, 1907. Maine (Lovell). Tab. 1. 



Resembles 0. atriventris. Also in Colorado, 

 mertensiee Cockerell, 1907. Florissant, Colorado, June (Rohwer). 



Visits Mertensia. 

 metitia Cockerell, 1909. Boulder, Colorado, April 17 (G. M. Hite). Tab, 7. 



Visits Rihes pumilum. 

 *montana Cresson, 1864. Pike's Peak, Colorado. 



Male with wings purely hyaline. 

 *nanula Cockerell, 1897. Seattle, Washington, April and May (Kincaid). 

 *nassa Cockerell, 1910. Claremont, California (Baker). Tab. 8. 



Paratype— Cat. No. 13439, U.S.N.M. 

 *nifoata Cockerell, 1909. Troublesome, Colorado, June (Rohwer). 



Abdomen of male with a ventral tooth. Allied to 0. odontogaster and 0. ashmmdii, 

 the three forming the subgenus Acanthosmioides. 



Paratype.— Cat. No. 14432 U.S.N.M. 

 *nigrifrons Cresson, 1878. Colorado (Morrison). Tab. 1. 5. 



Hair of pleura black, of scutellum light, with at most a few dark hairs intermixed. 

 Extends to Washington. 



A new locality is Diuango, Colorado, May 26, 1899 (Oslar). 

 nigrifrons subaustralis Cockerell, 1900. Beulah, New Mexico (W. Porter). 



Female 10 mm.; anterior margin of clypeus with a broad shallow emargination. 

 nigritula Friese, 1902. 



Belongs to Leucosmia, according to Titus, who redescribes the male; Proc. Ent. Soc. 

 Wash., vol. 7, 1906, p. 157 (as parvula). 

 * novomexicana Cockerell, 1903. Arroyo Pecos, Laa Vegas, New Mexico (W. P. 

 Cockerell). Tab. 1. 



Also in Colorado. Related to 0. grandjor. 



Type.— Cat. No. 6362 U.S.N.M. 

 oblonga Provancher, 18S2. = Monumetha albifrons. 



First described as a Megachile, and name preoccupied. 

 * odontogaster Cockerell, 1897. Olympia, Washington (Kincaid). 



Resembles 0. inurbana; second ventral abdomirial segment of male toothed. 



Paratype.— Cat. No. 3709, U.S.N.M. 

 olivacea Cockerell, 1907. Boulder, Colorado, April (W. P. Cockerell). Tab. 1. 



Female; Ann. and Mag. Nat. Hist., Aug., 1907, p. 127. 



Male with hind basi tarsus toothed. 



A vai-iety of the male (variety a) with the thorax above without black hairs, was 

 taken by Mr. S. A. Rohwer at Boulder, April 14, 1907, at flowers of Ribes pumilum. 

 parva Provancher, 1882. Canada. 



Same as nigritula. 



