448 SYSTEMATIC SYNOPSIS. —PICAEI^— CYPSELIFOMMES. 
rectrices. In certain genera, either wing or tail develops a pair of immensely lengthened 
feathers. Feet extremely small; tarsus usually short, and partly feathered; hind toe very 
short, commonly elevated and turned sideways; front toes connected at base by movable web- 
bing, and frequently showing abnormal ratio or phalanges, the 4th toe having but 4 joints 
(p. 127, fig. 41) ; middle toe lengthened beyond the short lateral ones, its claw usually pecti- 
nate (fig. 291). The oil-gland is nude, and cceca are present. The arrangement of the leg- 
muscles is anomalogonatous (p. 195) ; the ambiens and accessory femoro-caudal are both 
absent. 
A definitely-circumscribed, easily-recognized group of about 14 genera and rather more 
than 100 species, of temperate and tropical parts of both hemispheres. They are all more or less 
nocturnal, and have a certain resemblance to owls, — particularly the genus Steatornis, which is 
quite owlish. The flight is perfectly noiseless ; the plumage is very soft and lax, as in owls, 
and the colors are usually blended in the most intricate pattern. The Caprimulgidce are 
divisible, according to the structure of the feet, into two subfamilies : PodargincE, chiefly Old 
World, with the normal ratio of phalanges, and Caprimulgince (as below) . Considering, how- 
ever, other points, particularly the shape of the sternum, a more elaborate division is into (1) 
Podargince, phalanges normal, tarsus naked and lengthened, sternum doubly-notched, with 
three genera (Podargiis, Batrachostomus, and ^gotheles of the Old World ; (2) Nyctibiincs, 
phalanges normal, tarsus short, feathered, sternum doubly-notched, upper mandible toothed, 
containing one genus (Nyctihius) of tropical America ; (3) Steatornithince, phalanges normal, 
sternum singly-notched, with one remarkable genus (Steatornis) of tropical America, which 
might properly be made type of a separate family, so many are the peculiarities of this owlish 
bird ; and finally (4) CaprimulgincB, comprising the rest of the family. The latter alone is 
represented in North America. Our Whippoorwills " are typically caprimulgine, and give a 
good idea of the essential characters of the family; our ''Night-hawks" are more aberrant, 
representing a particular section of the subfamily ; but neither of these gives any hint of the 
singular shapes which some of the genera assume. 
30. Subfamily CAPRIMULCIN/E : True Goatsuckers; Night-Jars. 
Sternum singly-notched on each side behind ; its body not 
square. Ratio of phalanges abnormal. Outer toe ^-jointed; 
middle claw pectinate; hind toe very shorty elevated, semi-lateral; 
anterior toes movahly webbed at base (fig. 41); lateral toes not 
nearly reaching base of middle claw. Tarsus very short, com- 
monly much feathered (longer and naked in Nyctidromus and 
Phal(snoptilus) . Besides the semipalmation of the feet, there 
is another curious analogy to wading birds ; for the young are 
downy at birth, as in Prcecoces, instead of naked, as is the rule 
among Altrices. The plumage is soft and lax, much as in the 
Owls; the birds have the same noiseless flight, as well as, in 
most cases, nocturnal or crepuscular habits ; and some of them 
bear an odd resemblance to Owls. Besides this fluffiness and 
laxity of the plumage, the skin is very thin and tender ; it is 
difficult to make good specimens of the whippoorwills, and the 
curiously variegated blended shades, of exquisite beauty, like 
, , , , ^_ the powdery coloration of a moth's wings, are at best not easy 
Fig. 290.— Night-hawk, a glab- / .-, . -i , • i- x-u • ^v, • *i 
rirostral Caprimulgine. (From Ten- tO describe. An evident design of the capaciOUS mouth IS the 
ney, after Wilson.) capture of insects ; the active birds quarter the air with wide- 
open mouth, and their minute prey is readily taken in. But they also secure larger insects in 
other ways; and to this end the rictus is frequently strongly bristled, as in the Tyramiidts. In 
