Male with the upper parts ultramarine blue, the lower parts light chestnut-red, excepting the abdomen, which is white. Female with the upper parts dull greyish-blue, brighter behind; lower parts as in the male, but much duller. Young with the upper part of the head, hind neck, and part of the back greyish-brown, the rest as in the female, the lower parts light grey, the feathers on the breast and sides margined with brown. _Male_, 7, 10. _Female_, 6-1/2. Generally distributed from Texas to the Fur Countries. Vast numbers spend the winter in the Southern States. Columbia River. Migratory. Blue Bird, Sylvia Sialis, Wils. Amer. Orn. v. i. p. 56. Saxicola Sialis, Bonap. Syn. p. 39. Erythaca (Sialia) Wilsonii, Swains. & Rich. F. Bor. Amer. v. ii. p. 210. Blue Bird, Ampelis Sialis, Nutt. Man. v. i. p. 444. Blue Bird, Sylvia Sialis, Aud. Orn. Biog. v. ii. p. 84; v. v. p. 452. 135. 2. Sialia occidentalis, Townsend. Western Blue Bird. Plate CCCXCIII. Fig. 4. Male. Fig. 5. Female. Male with the upper parts and throat ultramarine blue; fore part of back, breast, and sides, light chestnut-red; rest of lower parts light blue, the abdomen whitish. Female with the upper parts dull greyish-blue, the back tinged with brown, the wing-coverts and rump brighter; lower parts pale red, the abdomen light grey. _Male_, 7; wing, 4-5/12. _Female_, 6-3/4. North California, and Oregon Territory. Abundant. Migratory. Sialia occidentalis, Western Blue Bird, Towns. Journ. Acad. Nat. Sc. Philadelphia, v. vii. p. 188. Western Blue Bird, Sylvia occidentalis, Aud. Orn. Biog. v. v. p. 41. 136. 3. Sialia arctica, Swains. Arctic Blue Bird. Plate CCCXCIII. Fig. 2. Male. Fig. 3. Female. Male with the upper parts light ultramarine, with a tinge of green; sides of the head, fore neck, and sides of neck, and the anterior half of the breast, light greenish-blue, that colour gradually fading into white behind. Female with the upper parts light greyish-brown, the rump and wing-coverts blue; fore part of neck and anterior portion of the breast reddish-grey, the rest of the lower parts pale brownish-grey. _Male_, 7-1/4; wing, 4-((7-1/2)/12). _Female_, 6-3/4; wing, 4-2/12. Columbia River, Rocky Mountains, and Fur Countries. Abundant. Migratory. Erythaca (Sialia) Arctica, Arctic Blue Bird, Swains. & Rich. F. Bor. Amer. v. ii. p. 209. Arctic Blue Bird, Sialia Arctica, Nutt. Man. v. ii. p. 573. Arctic Blue Bird, Sylvia Arctica, Aud. Orn. Biog. v. v. p. 38. FAMILY XII. TURDINÆ. THRUSHES.