322 SYSTEMATIC SYNOPSIS. —PASSEBES ~ OSCINES. 
159. H. erythrogas'tra horreo'rum. (Gr. ipvdpos, entthros, ruddy, and yaa-r^p, gaster, belly. 
Lut. horreorum, of barns, gen. pi. of horreum, a barn.) Barn Swallow. adult: deep 
lustrous steel-blue; forehead and entire under 
parts rufous, generally deepest on the forehead 
and throat ; an imperfect steel-blue collar. 
Wings and tail blackish, with steel-blue or 
somewhat greenish gloss ; the lateral pair of 
tail-feathers much lengthened and filiform at 
the end, all but the central pair with a white 
spot. Length 6.00-7-00, very variable, accord- 
ing to the development of the tail; extent 12.50- 
13.50; wing 4.50-5.00; tail 3.00-5.00, the fork 
2.00-3.00 deep. 9, adult: Quite like the ^; 
colors rather less intense and lustrous; average 
size smaller. Young : Lacking in great measure- 
the elongation and attenuation of the lateral tail- 
feathers, the fork being an inch or less in depth. 
Similar to the adults, but much duller, and with 
rather a greenish than steel-blue lustre — at an 
early age quite brown, with scarcely any lustre,, 
and the rump and upper tail-coverts skirted with 
rusty. Frontlet obscurely marked or reduced to. 
Fig. 18L — Generic details of /?mt??fZo (/t. /wr- a mere tawny line, and under parts, especially 
reorum, nat. size). (Ad nat. del. E. c.) hehmd the dark collar, very pale, even brownish- 
white. N. Am. at large ; abundant; breeds throughout its range. 
50. IRIDOPROC'NE. (Gr. ^Ipts, gen. ^'ipidos, Iris, messenger of the gods ; also the rainbow ; 
npoKVTj, Procne, daughter of Pandion.) Iris Swallows. Plumage compact, lustrous, as in 
Hirundo ; but tail lacking the elongation of that genus, being simply emarginate. Under 
parts snowy white. Eggs colorless. Sexes similar. 
160. I. bi'color. (Lat. hicolor, two-colored. Fig. 182.) White -bellied Swallow. adult:: 
Entire upper parts glossy dark green ; wings and tail blackish, lustrous ; lores black. Entire- 
under parts pure white. Bill black ; feet dark. Length 
about 6.00; extent 13.00; wing 4.50-5.00; tail 2.50. 
9 : Similar, the colors rather less intense and lustrous. 
Young : Birds of the year slowly acquire a plumage 
differing only in the less lustre and intensity from that 
of the adults; but, on leaving the nest, they are dark 
mouse-gray or slate-color above, including the wings 
and tail, the interscapulars and inner quills tipped with 
rusty ; and white below, slightly shaded with ashy ; 
thus curiously similar to Cotile riparia. The feet yel- 
low. The first plumage is worn longer than usual, the 
autumnal dress being slowly gained — one or two of fig. 182. — White-bellied Swallow, nat. 
the metallic-tinted feathers at a time. The quills of size. (Ad nat. del. E. C.) 
the Mdng are moulted by the young as well as by the adult, and in both, in autunm, the inner 
secondaries are white-tipped. Temperate N. Am. Breeds indiflPerently in all parts of its 
range, and winters abundantly on the southern border. 
51. TACHYCINETA. (Gr. raxvKivrjTos, tachuJcinetos , moving rapidly.) Violet-velvet 
Swallows. Similar to the last, but lacking lustre of the richly varied plumage of the 
upper parts. 
