98 LIFE-HISTORIES OF BIRDS 



composing materials are joined together, and to their sur- 

 faces of attachment. In some species of CaUocaJia^ the 

 entire nest is composed of thickened saliva, constituting the 

 " edible bird's nest" which is esteemed such an article of 

 luxury in the East. 



This family comprehends about fifty species which are 

 assigned to from six to eight genera. They are denizens of 

 temperate and warm climates, are mostly small birds, and 

 superficially resemble the Hirundinida ; but their affinities 

 are certainly not related to these Oscines. There are two 

 subfamilies which are clearly defined by the structural char- 

 acters of the feet ; viz. : Cypselinte, or typical Swifts, and 

 CJHBturtniz, or Spine-tailed Swifts, which are represented 

 by only a single species in Eastern Pennsylvania. 



Subfamily ChseturinSD. Spine-tailed- Swifts. 



Toes with phalanges of the normal number ; posterior toe. 

 never reversed, but occasionally versatile ; in a single species, 

 clearly elevated. Tarsi unfeathered. The principal genus 

 of this group is Ch&tura, which embraces fully one half 

 of all known species belonging thereto ; it has the tail feath- 

 ers stiff' and armed with a point which is formed by the pro- 

 jecting rhachis. 



Chsetura pelasgia, Stephens. 



The Chimney Swallow ranges through the eastern parts 

 of North America, from the Atlantic to the 5oth. parallel 

 of north latitude. Dr. Richardson failed to meet it in the 

 fur-bearing countries, but it was observed by Mr. Say at 

 Pembina, on the Red river, in Northern Minnesota. Its 

 western limit is supposed to be terminated by the Great 

 Plains, specimens having been captured as far west as Bijou 

 Hill in Nebraska. Mr. Allen found it quite common *in 

 Kansas ; and further to the south and west, Dr. Woodhouse 

 discovered it to be very abundant, especially throughout the 

 Indian Territory, and in portions of Texas, New Mexico, 



