HIRUNDINID^: SWALLOWS. 
323 
161. T: thalas'sina. (Gr. BoKdacnvos, thalassinoSj sea-green.) ViOLET-GREEN Swallow. 
adult : Entire under parts, including the sides of the head to just above the eyes, and an enlarged 
Huffy tuft on the flanks tending to join its fellow over the ruinp, pure silky white. Upper parts 
rich, soft, velvety-green, mixed with a little violet-purple; the crown of the 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-purple. These rich colors 
opaque, without gloss or sheen ; wings and tail blackish, with violet and purplish gloss. Bill 
black; feet brownish-black, small; iris brown; mouth pale yellow. 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 the less purity and intensity of the colors of 
the upper parts. In the very highest plumaged specimens, the back 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 
crown. Very young birds are like /. bicolor, though smaller, being dark mouse-gray above 
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 I. hicolor. Middle and Western 
Provinces, U. S. and adjoining portions of British America; E. to the Upper Missouri. Breeds 
throughout its range, and winters extralimital. A lovely species. 
62. PETROCHELI'DON. (Gr. TreVpa, petra, a rock ; xf^t^cbj/, clielidon, a swallow.) Cliff 
Swallows. 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 band, and usually a frontlet of different 
color from the rest of the upper parts ; imder parts not continuously white as in Tachycineia 
and Iridoprocne. The nidification peculiar ; eggs colored. Sexes alike. 
162. P. lu'nifrons. (Lat. liina, the moon, or a crescent; frons, forehead. Fig. 183.) Cliff 
Swallow. Eaves Swallow. Crescent Swallow. Mud Swallow. ^ 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 square. 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 of 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. 
63. CO'TILiE. (Gr. Ka>Ti\ds, kotilas, 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. 
