556 SYSTEM A TIC SYNOPSIS. — PICA RLE — CYPSELI. 



hiud toe frequently elevated, or versatile, or permanently turned sidevrays or even forward 

 (pamprodactylous) or the four toes tending to divaricate in right and left pairs ; lateral toes 

 nearly or quite as long as the middle ; anterior toes deeply cleft, with basal phalanges (in the 

 true Swifts) extremely short, penultimate very long, the number of phalanges frequently ab- 

 normal (2, 3, 3, 3, instead of 2, 3, 4, 5 ; see p. 133, fig. 40) ; claws sharp, curved, never pec- 

 tinate. Plumage compact, usually sombre and whole-colored, or only relieved with white ; 

 sexes alike and young little difi'erent (plumage softer, more varied, and young unlike adults, in 

 the genus Macropteryx). Sternum deep-keeled, widening behind, its posterior margin nor- 

 mally entire (exceptionally 2-fenestrate, in Macropteryx)] furculum stout, rather U- than 

 V-shaped. Volitorial ability very great. Nidification various, always peculiar. Eggs several 

 (except in the Tree Swifts), narrowly oval, white. Young hatched naked and helpless. 



" One of the most remarkable points in the structure of the Cypselidce is the great devel- 

 opment of the salivary glands. In all the species of which the nidification is known, the 

 secretion thus produced is used more or less in the construction of the nest. In most cases it 

 forms a glue by which the other materials are joined together, and the whole nest is affixed to 

 a rock, wall, or other object against which it is placed. In some species of Collocalia, how- 

 ever, the whole nest is made up of inspissated saliva, and becomes the ' edible bird's nest ' so 

 well known in the East." (Sclater.) 



The student will have observed that the characters of the MicropodidcB as above drawn 

 require several exceptions to be taken in the case of the genus Macropteryx (or Dendrochelidon) , 

 which contains five or six species of East Indian Tree Swifts, difieriug notably from other 

 Swifts. The osteological peculiarities of these birds are decided in several respects, aftecting 

 the bones of the skull, sternum, fore-arm, tarsus, and toes (see Lucas, Auk, Jan. 1889, 

 pp. 8-13). The plumage is peculiar, approaching that of Caprimulgine birds; the egg is 

 stated to be single, and the nidification to resemble that of the Frog-mouths (Batrachostomus). 

 The departure of the Tree Swifts from Micropodidce proper is on the whole in the direction 

 of the^ Caprimulgi. If we exclude this remarkable genus as the type of a separate family 

 Macropterygidce or Dendrochelidonidce, the remaining Swifts form a well defined family of 8 

 genera and about 75 species, inhabiting all the temperate and tropical regions of the globe. 

 They are divisible into two subfamilies, mainly according to the structure of the feet ; and both 

 of these divisions are represented in North America. 



Analysis of Subfamilies and Genera. 



MiCROPODlN^. Front toes with 3 joints apiece. Hind toe lateral or versatile. Tarsi feathered. 



Toes feathered. Tail not spiny Aeronautes 



Ch.etorin^. Front toes with 3, 4, and 5 joints from inner to outer. Hiud toe posterior or lateral, but not reversed. 

 Tarsi and toes naked. 



Tail emarginate, not mucronate C)/pseloides 



Tail rounded, mucronate ChcBtura 



Subfamily MICROPODIN/E : Typical Swifts. 



Ratio of phalanges abnormal, the 3d an^ 4th toes having each 3 joints like the 2d ; basal 

 phalanges of all the anterior toes very short (fig. 40). Hind toe reversed (in Micropiis or 

 Cypselus), or lateral (in Aeronautes and Pamjptila). Tarsi feathered (in Micropus) ; toes 

 also feathered (in Aeronautes and Panyptila). This subfamily contains about one-third of 

 the species of Swifts, most of which belong to the genus Micropus. This genus is chiefly Old 

 World, but two South American species are referred to it by late authority. Panyptila is a 

 neotropical genus, to which our Rock Swift has usually been referred ; but in Panyptila the 

 tail is deeply forked, with acuminate lateral feathers (compare Aeronautes^ below). There 

 are two species of Panyptila, P. cayanensis and P. sancti-hieronymi. An interesting feature 

 is shown by the group of Palm Swifts, in which, as first pointed out by Hartert, there is a 



