HIRUNDO. 299 



Hiruiido tlialassina. 



Hirundo tlialassina, Swaixson, Phil. Mag. I, 1827, 365 (Mexico). — Aur>. 

 Orn. Biog. 17, pi. 385.— Ib. B. A. I, pi. 46.— Brewer, N. A. Ool. 

 I, 1857, 102 (the fig. pi. v, fig. 74 of egg belongs to another species). 

 — Baird, Birds N. Am. 1858, 311.— Maxam. Cab. Jour. 1858, 101. 

 — Lord, Pr. R. A. Inst. Woolw. IV. 1864, 115 (Vancouver Isl. ; nests 

 iij holes of trees). — Cooper & Sdckley, P. R. R. Rep. XII, ii, 185 

 (W. T.). — Chelidon ihalassina, Boie, Isis, 1844, 171. — Tachycineta 

 tlialassina, Cab. Mus. Hein. 1S50, 48. — Petrochelidon tlialassina, 

 ScLATER & Salvin, Ibis, 1859, 13 (Guatemala). — Sclater, Catal. 

 1861, 39, no. 239.— Ib. P. Z. S. 1864, 173 (City Mex.) 



Hub. Western and middle piovinces of United States, south to Guatemala. 



Specimens from different localities, as well as from the same place, 

 vary somewhat in the shade of coloration. Sometimes, as in other 

 Swallows, the innermost secondaries are edged and tipped with 

 white, more or less conspicuously. Young birds are uniform lustre- 

 less grayish-brown above, something like Cotyle riparia, white 

 below, with perhaps a tinge of ashy across breast ; the upper sur- 

 face of wings and tail with a greenish gloss ; the whole side of 

 head, including loral region and around the eye, dusky, not white as 

 in the adult. The white feathers on the posterior inner face of the 

 tarsus are more conspicuous than in the adult, and reach nearly two- 

 thirds the way to the toes, but do not exist at the lower end as in 

 Cotyle riparia, which at once distinguishes them. All the feathers 

 of under parts, even of chin and throat, are gray at base, not white ; 

 those of breast plumbeous to near tips, with a central stripe of lighter 

 (concealed). 



Specimens (probably resident) from Cape St. Lucas are much 

 smaller than from Upper California, the wing measuring 3.95, the 

 tail 1.90 inches, while 1,895 measures 4.50 and 2.20, respectively. 

 No. 29,204, from a typical locality (Orizaba), measures 4.70 and 

 2.40. 



The fully fledged young bird differs so much in appearance from 

 the adult, that I was at one time inclined to consider them as differ- 

 ent species. The female is duller than the male, especially on the 

 head and rump. 



