350 



NORTH AMERICAN BIRDS. 



322C9 



Genmts STELGIDOPTERYX, Raiud. 



fitfl(ji(hj)trrji.r, BAinn, liinls X. Am. 18J8, :112. Olyi"', llininilo scrripcnnix, Aid. ) 



Okx, riiAK. Bill riitliur .'<iii!ill ; nostiil.'^ oval, siipcrinr, iiiarfrinod lichind, but srarcely 



lali'iiilly l)y mi'iiilininc, liiit not at all ovt'itiung; 

 the axes of llio outliiii; ciinvciiriiijr. Frontal 

 Icatlier.-i soft, and, like chin, without bri.-itics. 

 Taisi ('(pial lo middle toe without claw; the 

 upper end covcncil with featheis all round, 

 none at lower end. I{a.<al j(,iiit of middle toe 

 adherent externally nearly to end; internall)', 

 scarcely half. Lateral toes about eiiiial, their 

 claws not reaching; ')eyond base of middle daw. 

 Tail slinfhtly eniar^inale ; the feathers broad, and oliliipiely roun(le(l at end. Kdjre of the 

 winjj lough to the touch; the .shafts of the librilhe of outer web of outer primary pro- 

 lonfjed and bent at right angles into a short stilfhook. Nest (of S. sern'pennin) in holes 

 in banks ; eggs pure white, unspotted. 

 Color dull brown above. 



The great peculiarity of this penu.s cnnsist.s in the remarkable rou^lincss 

 of the edge of the wing, said to occur al.so in Psitlidoprociu-, Cva Tiie ob- 

 ject is uncertain, but is probably to enable the bird to secure a foothold on 

 vertical or inclined rock.s, among or on wliich it makes its nest. A favorite 

 breeding-place of »S'. xn-ripciitiifi is in the piers and alaitments of bridges, and 

 these hooks might render essential aid in entering into their Iioles. 



The birds of this genus have usually been referred to Cofi//r, which, how- 

 ever, they resemble only in color. The nostrils arc* exjiosed, instead ot being 

 overhung; the tarsus is bare below, not leathered, and the lateral claws are 

 considerably curved, and not reaching beyond the base of the lateral, as in 

 Coti/lr. The structure of the wing is very dillerent. 



There are at least five species or races of tliis geiuis in America, although 

 only one belongs with certainty to the I'nited States. A .second, liowevcr, 

 (S.fiilripc7nm), Mexican and Guatemalan, is not unlikely to occur in Arizona 

 or Xew Mexico. This differs in having the chin and throat reddish-fidvous, 

 not mouse-gray ; the belly tinged with yellow. 



Stelgidopterjrx serripennis, Bairp. 



BOTTOH-WINGED SWALLOW. 



Ilmnidi) serriiiennU, Arn. Orii. Tiing. IV, 1838, filKi. — In. Hirds Am. I, 1840. Ifl3, pi. li. 

 Coljih s. Box. f'onsp. 1S')0, 342. — Cassin. _IJiiF,wi:i!, N. Am. Oiil. I, IS;".", lOii, 

 pi. iv, fig. M (eggs). — liAiiiD, liinls X. Am. ISr.H. 313. - F-onn, I'r. li. A. Inst. IV, 

 18(i4, IKMHr. (Dhniihia). — CooPKR&SicKi.KV, 1'. [!. I!. licp. XII, ii, ISii (W. Terr.). 

 — Ukkiimann, W W. Ii. X ; Willinn.son's licp. 3(i (.Sun .Xntonio, Tex. ; bnciling). — 

 Cooi'Klt, Oru. Cid. I, 1870. 110. Sleltiidoiilrnjj- s. lUlltn, Itird.s N. Am. IS.'iS, 312; 

 Rev. 314. 



