238 THE ENTOMOLOGIST. 



12a. Collar all dark 12c. 



Collar partly light ..... Sp. from Colo. 



(and apparently the same from N. H. and Md.) 

 12c. Basal one-third of hind tibiae light . . Sp. from N. H. 



Basal one-fourth of hind tibia3 light 



Sp. from Calif, and Vane. I. 

 126. Collar all dark (excl. tubercles) .... lZd. 



Collar partly light ...... 12e. 



12rf. Markings yellow, clypeus all dark . . . varifrons. 



Markings whitish, clypeus with a transverse white 

 band ........ Sp. from Colorado. 



12*. Head longer, markings whitish . . . Sp. from Colorado. 

 Head shorter, markings yellow . . . Sp. from N. H. 

 Head shorter, markings whitish, lower half of 

 clypeus rufescent ..... Sp. from Nevada. 



Light band on lower edge of clypeus . elliptica. (Canada.) 



It may be useful, in conclusion, to give a list of the species 

 known from America north of the Isthmus of Panama. Full 

 bibliographical references will be found to those of Smith and 

 Cresson in Dalla Torre's recent catalogue of bees ; for the species 

 of Eobertson and the present writer see the most recent volumes 

 of 'Psyche,' Trans. Am. Ent. Soc, and Canad. Entom. 



(1.) Boreal species, extending more or less across the northern 

 part of the continent : — 

 P. basalis, Sm., 1853. P. pygmaa, Cr., 1869. 



P. varifrons, Cr., 1869. P. elliptica, Kirby, 1837. 



(2.) Species of the N.E. States, and Canada, W. to the plains: — 

 P. modesta, Say, 1837. P. saniculce, Rob., 1896. (111., la.) 



P. zizice, Rob., 1896. P. nelumbonis, Rob., 1890. (111.) 



? = a(jinis, Smith, 1853. P. illinoemis, Rob., 1896. (111.) 



P. pennsylvanica, Ckll.,1896. (Pa., P. sparsa, Cress., 1869. (Pa.) 



Va.') P. verticalis, Cress., 1869. (Mass., 



P. antennata, Cress., 1869. (N. J., Pa., Conn.) 



Md.) 



(8.) Species of the Atlantic seaboard, Fla. to N. J. : — 

 P. confiuens, Sm., 1853. 



(4.) Species of the Southern States, W. to the plains : — 

 P. schivarzii, Ckll.,1896. (Fla.) P. georgica, Ckll., 1896. (Ga.) 



P. fiammipes, Rob., 1893. (Fla.) P. triangularis, Ckll., 1896. (Ga.) 

 P. floridana, Rob., 1893. P. labiatifrons, Ckll., 1896. (Ga.) 



(5.) Species of S. Dakota, approaching the Rocky Mts. types : — 

 P. zizia, race dunningi, Ckll., nov. 



(6.) Species found west of the plains : — 

 P. mesillce, Ckll., 1896. P. bakeri, Ckll., 1896. 



syn. siibtilis, Fox MS., Ckll. P. citrinifrons, Ckll., 1896. 

 (preocc.) P. rtigosula, Ckll., 1896. (Colo. 



