101 HIRUNDINIDH, SWALLOWS. —GEN. 43. 
are not.very tangible, and there is little probability of their proving constant. 
Though the difference in the shape of the bill of the type specimens is evident (fig. 
52, a and b), yet this is no more than that oc- 
curring in Eastern specimens of unquestionable 
estiva. (See Prate uy, figs. 19, 20, a, 6.) It 
may, however, take rank as a geographical variety. 
Hepatic Tanager.  Ashy-red, or liver- 
brown, brighter red on the head and under 
parts; sides ashy-shaded; bill plumbeous 
Bb ge Oy Hu aele eee black, conspicuously toothed; 9 like that of 
the foregoing, but ashier on the back. Size of the last. New Mexico, 
Arizona, and southward. Bp., 302; Rip@way, Proc. Acad. Phila. 1869, 
1325: Coops, VAae eee ae be oe et Seis ne ee no ee ELPA ae 
Louisiana Tanager. g bright yellow, middle of back, wings, and tail, 
black ; head crimson; wings with two yellow bars. @ most nearly resem- 
bling that of rubra, but distinguished from this or any of the foregoing by 
presence of two whitish or greenish-yellow wing-bars, and much edging of 
the same color on the inner quills. Immature g shows the black of the 
back mixed with olive, and the head only tinged with red; at first it is like 
the @. Size of the first species. U.S., Rocky Mountains to the Pacific 
(not in Louisiana!). Wiuts., ili, 27, pl. 20, f. 1; Nurz., i, 471; Avup., iii, 
231, pl. 210; Bp., 303; Coop., 145. oa Leo eo oe EDO METAaEe 
Family HIRUNDINIDA. Swallows. 
Fissirostral Oscines. Bill short, broad, flat, deeply cleft, the gape wide and 
about twice as long as the culmen—it generally reaches to about opposite the 
eyes. Nasal fossz short, broad, the nostrils directed more or less upward, some- 
times circular and completely open, sometimes overhung by a straight flat scale. 
Rictus with a few inconspicuous bristles or none. Wings extremely long, of nine 
primaries, of which the first equals or exceeds the second, the rest being rapidly 
graduated, the ninth hardly or not half as long as the first ; secondaries and their 
coverts extremely short. Tail of 12 (rarely 10?) rectrices, usually forked, some- 
times forficate with filamentous outer feathers. Feet short and weak; tarsi 
scutellate (occasionally feathered), commonly shorter than even the lateral toes ; 
basal joint of middle toe adherent to one or both lateral toes ; toes with the normal 
number of phalanges. 
This is a perfectly natural group, well distinguished by the foregoing characters. 
The swallows alone represent, among Oscines, the fissirostral type of structure ; 
they have a close superficial resemblance to the swifts and goat-suckers of another 
order, but the relation is one of analogy, not of affinity, though all these birds 
were formerly classed together in the highly unnatural ‘“‘ order” Fissirostres. (See 
beyond, under Cypselide and Caprimulgide.) 
A hundred species of swallows are recorded; probably about three-fourths of 
them are genuine. They are distributed all over the world; the most generalized 
types, like Hirundo itself, are more or less cosmopolitan, but each of the great 
divisions of the globe has its peculiar subgenera or particular sets of species. Thus, 
-all the American groups except Hirundo and Cotyle are peculiar to this continent. 
At I a Nae 
