332 TTJRIiIDiE. 



nearly equal and longest, bastard primary 0'72 to 0-53 inch. Legs, 

 feet, and claws black. Length of wing -i'G to 4-4 inches (female 

 4-28), tail 2-So to 2-6, culnien 0-05 to U-6, tarsus 0-8S to 0-8. 



The female differs from the male in having the head and back 

 suffused with brown, the chin and throat greyish brown, the 

 chestnut of the breast and Hanks much duRer in colour, the belly 

 with very slight traces of bine, the axillaries and the under wing- 

 coverts being also very slightly suffused with blue. After the 

 autumn moult the feathers of the upper parts are obscurely tipped 

 with brown ; the quill- and tail-feathers have narrow pale margins 

 towards the tips, and the outer webs of the innermost secondaries 

 are blue. Birds of the year and yoimg hi first plumaye appear to 

 be unknown. 



The Mexican Bluebird appears to be a resident in the highlands 

 of Mexico. 



a. Ad. sk. Mexico. Henry Seebohm, Esq. [P.]. 



5. Sialia occidentalis. 



Sialia occidentalis, Tojvtisend, Journ. Phil. Acad. Nat. Sc. vii. p. 18S 

 (18.37) ; Audub. B. Amer. 8vo, ii. p. 176, pi. cxxxv. (18.j9). 



Sialia mexicana, Sivains. apud Bp. C'omp. List B. Eur. 4'- N. Amer. 

 p. 10 ( 1838) ; apud Gray, Gen. H. i. p. 184 (1846, partim) ; apud 

 Bp. Consp. i. p. 298 (1850, partim) ; apud Sclater, P. Z. S. 18-57, 

 p. 126 ; ajned Baird, Cass. 4" Laior. B. N. Amer. p. 223 (1858, 

 partim) ; apud Sol. Cat. Amer. B. p. 11 (1862, 2Mrtim) ; apud 

 Baird, Revieio, p. 63 (1864) ; a2md Gray, Hand-l. B. i. p. 230. 

 no. 3.313 (1869, partim) ; apud Cooper, B. Calif, ed. Baird, p. 28 

 (1870) ; apud Coues, Key N.-Amer. B. p. 76 (1872) ; apud Coues, 

 B. N. West, p. 14 (1874, partim) ; aimd Baird, Breicer, Sf Bidyw 

 Hist. N.-Amer. B. i. p. 65 (1874, partim) ; apud Coues, Birds 

 Colorado Vail. p. 80 (1878, partifn) ; ajntd Salv. Sf Godm. Biol. 

 Centr.-Amer. Zool., Aves, i. p. 47 (1879, partim). 



Sylvia occidentaUs (Towns.) , Audub. Orn. Bioyr. v. p. 41, pi. cccxciii. 

 fig. 4 (1839). 



Sialia csendeocollis, Vigors, Zool, Voy, Blossom, p. 18, pi. iii. (1839). 



This form differs from the preceding in having the indigo-blue of 

 the upper parts replaced by brilliant metallic cobalt-blue, and in 

 having the brown on the upper parts much more developed, in some 

 examples the upper back and scapulars showing little of no traces 

 of blue. In other respects the two forms do not differ in colour, 

 but this form appears to be always smaller in size. Length of wing 

 4'2 to 4-05 inches (females 3-48 to 3'35), tail 2*6 to 2-35, culmen 

 0-63 to 0-56, tarsus 0-88 to 0-8, bastard primary 0-65 to 0-5. 



The female differs from that of the preceding in having the blue 

 of the wings, rump, upper tail-coverts, and tail of the same cobalt- 

 blue as the male, and in having the back miich more suffused with 

 brown. The changes which take place after the autumnal moult 

 are the same as in the preceding form. Birds of the year appear 

 to be unknown, but young in first j)lumarje are scarcely distinguish- 

 able from those of S. sialis. 



The Western Bluebird appears to be a resident in the mountains 



