174 COMMON BLUE-BIRD. 



Saxicola Sialis, Bonap. Syn.. p. 39. 



Erythaca (Sialia) Wilsonii, Swains, and Rich. F. Bor. Amer., vol. ii. p. 210. 



Blue-bird, Ampelis Sialis, Nutt. Man., vol. i. p. 444. 



Blue-bird, Sylvia Sialis, Aud. Orn. Biog., vol. ii. p. 84; vol. v. p. 452. 



Adult Male. 



Bill of ordinary length, nearly straight, broader than deep at the base, 

 compressed towards the end; upper mandible with the dorsal line convex, 

 the tip declinate, the edges sharp. Nostrils basal, oval. Head rather large, 

 neck short, body rather full. Feet of ordinary length, slender; tarsus 

 compressed, covered anteriorly with a few long scutella, acute behind, 

 scarcely longer than the middle toe; toes scutellate above, the two lateral 

 ones nearly equal; claws arched, slender, compressed, that of the hind toe 

 much larger. 



Plumage soft and blended, slightly glossed. Wings of ordinary length, 

 broad, the first quill longest, the second scarcely shorter, the secondary quills 

 truncato-emarginate. Tail rather long, broad, nearly even, of twelve broad, 

 rounded feathers. Short bristle-pointed feathers at the base of the mandible. 



Bill and feet black, the soles yellow, iris yellowish-brown. The general 

 colour of the upper parts is bright azure-blue, that of the lower yellowish- 

 brown, the belly white. Shafts of the quills and tail-feathers dusky. 



Length 7 inches, extent of wing 10; bill along the ridge -|, along the edge 

 f; tarsus y^. 



Adult Female. 



The female has the upper part of a tint approaching to leaden, the 

 foreneck and sides yellowish-brown, but duller than in the male, the belly 

 white. 



Length 6^ inches. 



Young Bird. 



When fully fledged, the young have the upper part of the head, the back 

 of the neck, and a portion of the back broccoli-brown; the rest of the upper 

 part much as in the female. The lower parts are light grey, the feathers of 

 the breast and sides margined with brown. 



In a male preserved in spirits, the roof of the mouth is flat, and similar 

 to that of the Thrushes; the tongue triangular, deeply emarginate and 

 papillate at the base, very thin, flat above, horny towards the end, tapering 

 to a slit point, and having the edges lacerated. The oesophagus, a b c, is 2^ 

 inches long, its width at the upper part 4 twelfths; the proventriculus, b 

 c, large. The stomach, d e, is of moderate size, broadly elliptical, a little 

 compressed, S twelfths long, 7 twelfths broad; its muscles distinct, the 

 lateral of considerable thickness, the lower very thin, the tendons elliptical; 

 the epithelium tough, dense, with longitudinal rugas. The intestine, efg h 



