20 Zoologia: N. Y. Zoological Society. [Vol. I 



of the year. One of these birds was immediately confined in the 

 superhumid atmosphere of the experimental cage, while the 

 other was allowed the freedom of a large outdoor aviary in com- 

 pany with song sparrows, tree sparrows, juncos and indigo bunt- 

 ings. The food was uniform in both cases, canary and millet 

 seed with lettuce, and some insect food. No hemp was ever 

 given. 



In May, 1902, when closely compared, no difference could 

 be detected between the two birds, and when placed together 

 during examination in a cage, it would have been impossible to 

 identify the individuals in order to return them to their respect- 

 ive quarters, if a primary had not previously been clipped 

 from the wing of one. 



In the following year. May, 1903, a radical change had taken 

 place in the bird confined indoors. The general effect was much 

 as in the yellow phase of the undulated grass parrakeet, Melop- 

 sittacus unchdatus, only in the case of the white-throated spar- 

 row it was a veil of darkness which appeared to be drawn over 

 the normal markings. In October, 1904, both birds having com- 

 pleted their winter moult, they were chloroformed and made into 

 skins. 



The white-throat which had lived the three years of its life 

 outdoors is in all respects normal, and, except in minor details 

 referable to individual variation, the bird is indistinguishable 

 from others in my collection. 



The other specimen of Z. albicoUis is melanistic to an ex- 

 treme degree. The deviation from the normal coloration of these 

 changes may best be appreciated by an examination of the pho- 

 tograph of the two birds. (Fig. 3.) 



In the melanistic bird there is a considerable increase in 

 all black and rufous markings, the latter color taking the place 

 of the normal buff, gray and white. On the wings and body there 

 is reduction or even obliteration of all yellow markings, and on 

 the head and throat a similar recessive tendency of the white. 

 It was recorded while making the birds into skins that the man- 

 dibles of the melanistic individual were deeply pigmented while 

 the legs and feet were normal in color, and these characters are 

 still conspicuous. 



The gray of the breast remains almost unchanged, but 

 there has appeared in this region a number of broad streaks of 

 dark brown, almost black, which at the posterior edge of the 

 gray area become confluent to form a large pectoral black spot. 

 In the living bird these streaks and pectoral mark were especially 

 noticeable, even more so than they are in the skin. 



