114 EXPLORATIONS AND SURVEYS WEST OF 100TH MERIDIAN. 



cinereus, where the chestnut of the back extends over the wing-coverts 

 and inner secondaries. The bill above is brownish -black, below whit- 

 ish, thus differing from caniceps, which has a flesh-colored bill, and 

 apparently approaching cinereus, where it is black above, below yellow. 

 Like cinereus, also, the pale ash of the throat fades gradually into the 

 white of abdomen, instead of being, as in caniceps, abruptly defined. Of 

 quite a large series of specimens collected by myself the past season, 

 and others in the Smithsonian collection, I have seen none which are 

 not readily assignable to one variety or the other by the distinctive 

 features pointed out. The theory of hybridization, which might be 

 admissible were only one or two specimens known possessing interme- 

 diate characters, seems wholly inadequate as an explanation in the case 

 of either annectens or dorsalis, where the forms extend over very exten- 

 sive regions, and preserve their distinctive characteristics intact. 

 Whether cinereus of the table-lands of Mexico, with a local variety, 

 alticola of the mountains of Guatemala, may not justly be entitled to 

 specific rank, is a matter of considerable doubt. While the typical 

 forms of caniceps and cinereus are widely different, dorsalis, intermediate 

 in its habitat, seems also intermediate in its characters, and it therefore 

 may be best to treat the two (caniceps et cinereus} as only separable as 

 varieties rather than as distinct species. A large suite, however, of 

 these birds collected in Mexico, which at present is wanting, might shed 

 more light on the subject. 



65. Junco liyemalis (L.), var. aikeni, Eidg. White-winged Snowbird. 



This race of the common snow-bird (hyemalis) is found late in the 

 fall and winter, distributed over quite a large area in the middle Eocky 

 Mountains of the United States. I found it and the two succeeding 

 forms, mingled indiscriminately in large flocks, in El Paso County, Colo- 

 rado, the middle of December. Mr. Aiken has had abundant opportunity 

 to note the time and manner of its migrations, and from these it seems 

 pretty certain that it finds its summer-home very far to the northward. 

 According to Mr. Aiken, the first stragglers from the north do not make 

 their appearance till about the 5th of October, and then in gradually 

 increasing numbers till the 1st of December, when they come in large 

 flocks, the last to arrive being the old and i'ully-plumaged males. While 

 many of the females and young birds proceed farther to the south, the 

 greater number of the adult males winter at some point farther to the north 

 than El Paso County, as of the whole number seen during the winter only 

 about two-fifths are males. Early in February the old birds begin to start 

 northward, the general migration being delayed about a month. The 

 habits of this race do not differ from those of its congeners. 



66. Junco oregonus, (Towns.) Oregon Snowbird. 



Found abundantly in the neighborhood of Bayard, N. Mex., and 

 generally distributed from this point northward, keeping in the low 

 foot-hills and along the streams on the plains. Mr. Aiken informs me 

 that comparatively but few of this species remain during the winter in 

 his section, the greater proportion passing on still further to the south. 



