MUSEUM OF COMPARATIVE ZOOLOGY. 157 



The others were intermediate between this form and the so-called' Z. 

 Gambeli.* 



20. Junco "caniceps." Abundant at Fairplay, and generally common 

 near the borders of the Park. 



21. Melospiza melodia. Occasionally seen along the streams, but no- 

 where very common. Song undistinguishable from that of the eastern 

 bird. Nest and eggs similar. 



22. Melospiza Lincolnii. Abundant along the streams, and especially 

 numerous near the mountains. 



23. Spizella socialis. Not common. But one specimen obtained, and 

 but few observed. The one obtained is scarcely distinguishable from east- 

 ern examples, except in being a little lighter colored^ 



24. Calamospiza bicolor. But few seen in the Park, and only near 

 its eastern border. Numerous at one or two points on the road from South 

 Park to Colorado City. 



25. Pipilo chlorurus. Common near the streams. 



ICTERIDJE. 



2G. Molothrus pecoris. Moderately frequent. 



27. Sturnella ludoviciana. Abundant. One of the characteristic 

 species of the open portions of the Park. 



28. Scolecophagus cyanocephalus. Abundant, keeping mainly near 



the streams. Young full-fledged, and most of the old birds moulting before 



the middle of July. 



CORVIDJE. 



29. Corvus corax. A few pairs observed near Fairplay. 



30. Pica caudata, var. hudsonica. Frequent along the streams. 



* The sole difference which has been supposed to constantly separate Z. Gambeli from 

 Z. leucophrys consists in the superciliary stripe being continuous to the bill in Z. Gam- 

 bell, while in Z. leucophrys it terminates at the anterior canthus of the eye, being cut off 

 at this point by a black line running from the eye to the black stripe on the head, or by 

 the black extending down, so as to cover the lores. The extension of the black over the 

 lores is, however, quite variable, especially in specimens from the Rocky Moun- 

 tains. In individuals referable to Z. leucophrys, the black covers the lores completely; 

 in others it extends only as low as the middle of the eye, and in others again not as low 

 as the eye, the ash in front of the eye being cut off from the superciliary stripe by a 

 short narrow black line running upward from the anterior canthus. This line is some- 

 times quite broad and distinct, or it is dotted with ashy feathers, or is reduced to a few 

 black feathers separated by ashy ones;. in which case it is difficult to say whether the 

 specimen should be called Z. leucophrys, with the black line reduced to scattered feath- 

 ers, or Z- Gambeli, with a few black feathers in the superciliary stripe. Notwithstanding 

 this, the ruses are few in which the specimen cannot be referred by this criterion to one 

 or the other series. Yet the irregularity of the extension of the black over the lores in 

 either race, and the evident transition between them, seems to render their specific sep- 

 aration questionable; their true relations being more those of geographical races. 



