HIRUNDINID2E : SWALLOWS. 323 



161. T. thalas'sina. (Gr. fiaXaero-ii/os, tlmlassinos, sea-green.) Violet-green Swallow. ^, 

 adult : Entire under parts, including the sides tif the head to just above the eves, and an enlarged 

 fluffy tuft on the flanks tending to join its fellow over the rump, pure silky white. Upper parts 

 rich, soft, velvety-green, mixed with a little violet-purple; the crown of tlie head similar, but 

 rather greenish-brown, with a purplish tinge. Cervical region, in some cases a well-defined 

 though narrow cervical collar, and the upper tail-coverts, violet-pur|)le. These rich colors 

 opaque, without gloss or sheen ; wings and tail blackish, with violet and jiurplish gloss. Bill 

 black; feet brownish-black, small; iris brown; mouth pale yeUow. Length 4.50-5.00; 

 extent 11.50-12.50; wing 4.50; tail 2.00, lightly forked; bill 0.25; tarsus 0.40. The 9, 

 and immature birds in general, differ simply in tlic less purity and intensity of the colors of 

 the upper parts. In the very highest plunuiged specimens, the ba(di is nearly pure green, 

 the cervical collar distinct, and the several contrasts of crown, collar, back, and upper tail- 

 coverts are strong ; in general, the back has a brownish-purple shade, more like that of the 

 croivn. Very young birds are like I. licolor, though smaller, being dark mouse-gray abovi; 

 and white below. But traces at least of the special tints speedily appear. Young or autumnal 

 birds usually have the inner secondaries white-tipped, as in /. hicolor. Middle and Western 

 Provinces, U. S. and adjoining portions of British America; E. to the Upper Missouri. Breed.s 

 throughout its range, and winters extrahmital. A lovely species. 



52. PETROCHELI'DON. (Gr. Trerpa, petra, a rock ; xf^'So"', chelidon, a swallow.) C'i>iff 

 SwALLOA\"S. Bill stout and deep (for this family) ; nostrils superior, opening without nasal 

 scale. Tail unusually short, the tips of the folded wings reaching beyond it, about even, or 

 only slightly emarginate, with the feathers broad to their ends. Feet much as in Hirundo ; 

 tarsi feathered above; toes extensively adherent at base. A bristly appearance of the' front 

 and chin, different from what is seen in other groups. The tuft of crissal feathers is full, 

 reaching nearly to the end of the tail. The species agree well in a special pattern of coloration, 

 being steel-blue above, with rufous rump and nuchal liand, aud usually a frontlet of difi'eient 

 color from the rest of the upper parts ; under parts not continuously white as in Tachycineia 

 and h-'idoprocne. The nidification peculiar ; eggs colored. Sexes alike. 



163. P. lu'nifrons. (Lat. lima, the moon, or a crescent ; froiis, forehead. Fig. 183.) Cliff 

 Swallow. Eaves Swallow. Crescent Swallow. Mdd Swallow. (J 9 , adult : 

 Back and top of head, with a spot on the throat, deep lustrous steel-blue, that of the crown 

 and back separated by a grayish nuchal collar. Frontlet white 

 or brownish-white. Shorter upper tail-coverts rufous. Chin, 

 throat, and sides of head intense rufous, sometimes purplish- 

 chestnut, prolonged around the side of the nape. Under parts 

 dull grayish-brown, with usually a rufous tinge (rusty-gray), 

 and dusky shaft-lines, whitening on the belly, the under tail- 

 coverts gray, whitish-edged and tinged with rufous. Wings 

 and tail blackish, with slight gloss. Bill black ; feet brown. 

 Length 5.00-5.50; extent 12.00 or more; wing 4.25-4.50; tail 

 2.25, nearly sciuare. Sexes not distinguishable ; both vary much 



in the tone of coloration, especially of the rufous parts. Fore- Fig. 183. -Cliff Swallow, nat. 

 head sometimes white, sometimes quite brown. In young birds, '*'^''- <-^'' °^'- <^"^'- ^- *^-> 

 the frontlet may be altogether wanting ; upper parts lustreless dark brown, most cjf the 

 feathers being skirted with whitish ; the rufous of the throat and rump a mere tinge, the spot 

 on the throat wanting, and the parts often speckled with white. N. Am. at large, abundantly 

 but irregularly distributed, breeding in colonies wherever suitable sites may be found for its 

 curious retort-shaped or bottle-nosed nests of mud. 



53. CO'TILE. (Gr. KfflTiXat, Icotilas, a babbler, twitterer.) Bank Swallows. Tarsus with a 

 tuft of feathers at the base below, near insertion of the hind toe. Edge of wing not rough. 



