88 



BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



width of bill at frontal antise, 4-5 (4.7); tarsus, 11.5-13 (12); middle 

 toe, 10.5-12 (11.6)." 



Young. — Above, including sides of head and neck, uniform soft 

 dark mouse gray, the tertials margined terminally with brownish 

 white, beneath white, usually faintly shaded across chest with pale 

 grayish brown. 



North America in general; north to Alaska (Kowak Eiver, JPoBt 

 Yukon, etc.), Mackenzie (Fort Simpson, Fort Norman) and Ungava 

 (Fort Chimo); breedmg southward to Virginia (King William County; 

 Snniths Island), Mississippi (Jackson), Kansas, Colorado, Utah, 

 Nevada, and California; wintering from South Carolina (occasionally 

 northward to New Jersey) and the Gulf States southward to the Baha- 

 mas (New Providence Island), Cuba (occasional only ?) and over greater 

 part of Mexico to highlands of Guatemala (Duenas; Pajal Grande; San 

 Geronimo); occasional in Bermudas; accidental in British Islands. 



Hirundo bicolor Vibillot, Oia. Am. Sept., i, 1807, 61, pi. 31; Enc. M6tli., ii, 1823, 

 520.— Stephens, Shaw's Gen. Zool., x, 1817, 105.— Swainson and Richakd- 

 soN, Fauna Bor.-Am., ii, 1831, 328.— Audubon, Om. Biog., i, 1831, 491, pi. 98; 

 Synopsis, 1839, 35; Birds Am., oct. ed., 1, 1840, 175, pi. 46.— Hurdis, Jar- 

 dine's Contr. Orn., 1850, 35 (Bermudas, Sept.).— Lembeye, Aves de la Isla 

 de Cuba, 1850, 46, pi. 7, flg. 2. — Cabot, Naumannia, ii, heft, iii, 1853, 65 

 (Lake Superior). — Cassin, Illustr. Birds Cal., Tex., etc., 1855, 244. — Henky, 

 Proc. Ac. Nat. Sci. Philad., 1855, 308 (New Mexico); 1859, 106 (do.).— 

 Bryant, Proc. Bost. Soo. N. H., vi, 1857, 115 (Nova Scotia). — Brewer, Proc. 

 Bost. Soc. N. H., vi, 1857, 148 (California); N. Am. Ool., 1857, 100, pi. 4 

 (egg).— Baird, Eep. Pacific R. E. Surv., ix, 1858, 310; Cat. N. Am. Birds, 

 1859, no. 227;' Review Am. Birds, 1865, 297.— Xantus, Proc. Ac. Nat. Sci. 



o Fourteen specimens. 



Eastern specimens compare with western in average measurements as follows: 



Ixjcality. 



Wing. 



Tail. 



Ex- 

 posed 

 culmen. 



Width of 

 bill at 

 frontal 

 antise. 



Tarsus. 



Middle 

 toe. 



Depth 

 of fork 



of 

 tail. 



MALES. 



Seven adult males from eastern United 

 states 



Two adult males from Rocky Mountain 

 district 



Seven adult males from western United 

 States 



FEMALES. 



Six adult females from eastern United 

 States 



Two> adult females from Rocky Mountain 

 district 



Six adult females from western United 

 States 



118.4 

 119.2 

 115.9 



114. B 



116.5 

 « 



55. 6 

 68.2 

 55.1 



54.7 

 55.2 

 64 



6.9 

 6.2 

 5.9 



6.4 



6 

 6 



5.4 

 4.7 

 4.6 



4.9 

 4.5 

 4.5 



12. S 

 12.5 

 11.5 



12.2 

 12.2 

 11.8 



11.6 

 12.2 



n.2 



11.9 

 11.5 

 11.4 



9.4 

 9.5 



8.7 



7.7 

 7.8 



I am not able to perceive any difference in color between eastern and western 

 specimens, both series varying between exactly the same extremes. 



