72 



Clark, Pterylosis of Swifts and Hummingbirds. 



r.Auk 

 LJan. 



teryx there are 10 or 11 secondaries and the wing is aquincubital. 

 Except in Macropteryx and Collocalia, the skin on the hand is 

 very dark, and this darkening extends in some cases not only along 

 the forearm but nearly to the shoulder. 



The above account of the cypseline pterylosis is based upon the 

 examination of 15 swifts, representing 10 species and 8 genera. 

 Nitzsch ('40) studied Hemiprocne collaris Temm., H. acuta (Ci/ps. 

 acutus Pr. Max v. Neu Wied.) and Cypselus apus; Shufeldt ('88), 

 Choetura pelagica, Aeronautes melanoleucus, and Cypseloides hig'er; 

 and Thompson (:01), Collocalia epodiopyga; but so far as I know, 

 the pterylosis has not been examined in any others of the Cypseli. 

 The genera will now be considered in detail. 



Macropteryx. 



It is especially noteworthy that the pterylosis of this interesting 

 genus does not differ in any essential point from that of Chwhira. 

 The nuchal apterium is present but is quite small, as the upper 

 cervical tract is comparatively long and narrow. The femoral 

 tracts are notably strong posteriorly. The legs are feathered about 

 to the tarsal joint. The skin on the hand is not dark. The 10 

 rectrices, 10 primaries, 11 secondaries, and 3 alula feathers are 

 not peculiar, but the wing is aquincubital. 



Specimen examined. 



Collocalia. 



The single specimen of this genus which I was able to examine 

 was in poor condition, but the only points in which its pterylosis 

 appeared to differ from that of Chainra is in the shape of the upper 

 cervical tract, which is longer and narrower, and the nuchal apte- 



