414 ORNITHOLOGY. 



the West riuinboldt Moniituins it was very nnmei-ous in September. It 

 was found there in ever-restless companies, continually twittering as they 

 flew from bush to bush, at which time the flocks became greatly scattered, 

 the individuals straggling, or "stringing out," one behind another. In 

 all their movements they were remarkably restless, in this respect even 

 surpassing the Gnat catchers (Polioptilce), to whicli they bear considerable 

 resemblance in their movements and appearance. In November many of 

 these birds were seen in company with the Gray Titmice {Lophophanes 

 inornatus) among the cedars on the Pea-vine and Virginia Mountains, and 

 adjacent ranges in western Nevada, and in the spring one or two flocks, 

 supposed to be this species, were observed in the gorge of the Carson River, 

 near Carson City. On the eastern side of the Great Basin a few individuals 

 in City Creek Caiion, near Salt Lake City, comprised all that were seen. 



Among the numerous specimens killed in September, we noticed that 

 many had the ii'is bUickish, while in others it was clear light sulphur- 

 yellow, and in some intermediate, or yellowish outwardly, and brownish 

 next the pupil. A close examination, however, of these specimens, showed 

 that this diiference apparently depended on age, those having the darkest 

 eyes being unmistakably young birds, while those in which the iris was 

 clear yellow were all old birds, as was readily detected by the difierence 

 in the texture of their plumage. Even tlie youngest specimens had a 

 yellowisli outer ring to the iris, concealed by the eyelids, so that it seems 

 that this color gradually spi-eads from the outside to the pupil, with 

 advancing age, until, when fully mature, the iris becomes wholly clear 

 light yellow. 



List of specimem. 



171, <JJMi'.; West Humboldt Monutains, Nevada, September 7,1867. 4J — G— 2 

 — H4 — rV — TIT- I^'"i black; iris, sepia-hlach, very narrow outer yellowish ring; tarsi 

 and toes, black. 



1S4, 9 ad; We.st Humboldt Mountains, September 11. 4J— 5J— 2— li-i— J— -A, 

 — 2| — If. Bill, black; iris, light yclloir ; tarsi and toes, black. 



185, S jui\; 4i— G— 2 — Iji — \ — fj. — 2jL — 1. Iris, light yellow, brownish next 

 pupil. 



250, ad.; West Humboldt Mountains (east side), October 12, 1867. 4^-^— 6— 2J 

 — If— i— r®B — 2 J — 1|. Bill, tarsi, and toes, deep black; iria, sulphur-yellow. 



