(YrSELID.E — TIIK SWIFTS. 497 



hinidred feet lii"j;Ii. It seemed to be very wary, and flew witli great velocity, 

 rarely descending vvitliin reach of the guns. 



Tlie White-throated Swift was met with in great abundance l»y Mr. Kidg- 

 way at the East Hund)oMt Mountains, and was seen l)y him more si»aringly 

 in the Tovabe and Wahsatch. In tlie former mountains it inhabited tlie hiiih 

 limestone clilfs which walled the canons, congregating in thousands, and 

 nesting in the chinks or crevices of tlie rocks, in company with the Violet- 

 green Swallow {Tavhifrlncta thiiltKO^iiui). It was a very ncjisy species, having 

 a vii'orous chatter, reminding one somewhat of the notes of voung lialtimore 

 Orioles when being fed by their i>arents. It was also very pugnacious, a 

 cou})le now and then being seen to fasten upon one another liigh u}) in the 

 air, and, clinging together, falling, whirling round and round in their descent, 

 nearly to the ground, when they would let go each other, and separate. 

 A couple would often rush by with almost inconceivable veh)city, one in 

 chase of the other. Their flight was usually very high, or, if they occasion- 

 ally descended, it was so swiftly that Mr. Kidgway only succeeded in shoot- 

 ing three specimens, while he found it utterly impossible to reach their nests, 

 which were in the horizontal fissures in the face of the overhanging cliff. 



Subfamily CHiETURINiE. 



This subfamily is characterized by having the normal number of phalanges 

 to the middle and outer toes (4 and 5, instead of 3 and 3), the backward 

 position of the hind toe, and the naked tarsi, which do not (;ven appear to 

 be scutellate, but covered witli a soft skin. Of tlie two Xorth American 

 genera, Chainrn has spinous projections at the end of the tail-feather.>5, 

 while in Neplurcetcs tlie shafts of the tail-feathers, though stifl'ened, do not 

 ])roject beyond the plume. 



• This subfamily appears to 'be composeil of two* definable sections, with 

 subdivisions as follows : — 



A. Tail forked ; spinous point^s of the feathers not extending far beyond the 

 Avebs, or entirely wantintr. Feathering of the sides of the forehead extending 

 forward outside the nostrils nearly to their anterior end. 



a. No trace of spinous points to tail-feathers. Feathering of frontal points 

 almost completely enclosing the nostrils between them. Xo lii^jjt collar 

 round the neck ; sides of the forehead with a hoar}' suffusion . . Xephcccetea. 

 h. Spinous points of tail-feathers distinct. A light collar round the neck. 



1. Xostiil a*; in Xephwcetes. Sides of forehead with a hoary suffusion. 

 Collar chestnut. Win.ir less than '>..')(). (C. rntila.) 



2. Feathered frontal points narrower, not reaching anterior end of 

 nostril. Sides of forehead without hoary suffusion Collar white. 



Wing more than 8.00 Hemiprocne. 



B» Tail rounded; spinous points of the feathers nuich elongated and projecting. 

 Feathering of sides of forehead scarcely reaiihing beyond posterior end of nostril. 

 Wing less than 5.50 ChccUira, 



