422 



NORTH AMERICAN BIRDa 



usual ; but in the Cypsdimr tliey are 2, 3, 3, and 3, as sliown in the accora- 

 i)jinvin«' cut borrowed from Dr. Sclater's masterly memoir on the CypsclUhv, 

 (Tr. Zool. Soe. London, 18G3, 5^3), which also serves as the basis of the 

 arrangement here presented. 



Left foot of Chtftiira zonaris. 



Left foot of Panyptila melanoleuea. 



Cypselinae. Tarsi featlu'ivd ; phalanges of the middle and outer toes three 

 each (instead of four and live). Iliml toe directed either forward or to one 

 side, not backward. 



Tarsi leathered ; toes hare ; hind toe directe<l forward . . . Cypselus. 

 Both tarsi and toes feathered ; hind toe lateral .... Panyptila. 



Chaeturinse. Tarsi bare: phalanges of toes normal (four in middle toe, 

 five in outer). Hind toe directed backwards, though sometimes versatile. 

 Tarsi longer than middle toe. 

 Tail-feathers spinous. 



Shafts of tail-feathers projecting beyond the plumage 

 Shafts not jirojeeting, (Xephcecetes) 

 Tail-feathers not spinous ...... 



Tarsi shorter than middle toe 



Chcetura. 



Ci/pseloiiles. 



CoUocaUia. 



DendrocheUdon. 



The Swifts are cosmopolite, occurring throughout the globe. All the 

 genera enumerated above are well represented in the New World, except 

 the last two, which are exclusively East Indian and Polynesian. Species of 

 CoUovaUla make the " edible bird's-nests " which are so much sought after in 

 China and Japan. Tliese are constructed entirely out of tlie hardened saliva 

 of the bird, although formerly supposed to be made of some kind of sea- weed. 

 All the Ci/pseli(f(r have the salivary glands highly developed, and use the secre- 

 tion to cement together the twigs or other substances of which the nest is con- 

 structed, as w^ell as to attach this to its support. The eggs are always white. 



There are many interesting peculiarities connected with the modification 

 of the Ci/pselidcc, some of wiiich may be l)riefly adverted to. Those of our 

 connnon Chinmey Swallow^ will be referred to in the proper place. Panyp- 

 tila saiicti-hicronyma^ of Guatemala attaches a tul)e some feet in length to 

 the under side of an overhanging rock, constructed of the pappus or seed- 

 down of plants, caught flying in the air. Entrance to this is from below, 

 and the eggs are laid on a kind of slielf near the top. Chwtura poliiira of 

 Brazil again makes a very similar tube-nest (more contacted l)elow) out of 

 the seeds of Trixis divaricata, suspends it to a horizontal branch, and covers 



