134 CALIFORNIA ACADEMY OF SCIENCES. 



general shade of a part of the feather was dusky, as if 

 only a thin layer of black pigment had been deposited. 

 In other specimens various stages of transition were 

 observable, from the example figured to instances 

 where the entire tail was black with simply a few little 

 isolated irregular patches of yellow. 



Dr. C. Hart Merriam has published an instance of a 

 seasonal change of color occurring by the introduction 

 of pigment without moult, although his views are not 

 accepted by Mr. Ridgway in his Manual. With regard 

 to Allen's ptarmigan (Lagopus lagopus alleni), the bird 

 in question, Dr. Merriam writes:* " The large series 

 of wings sent by Mr. Comean demonstrates beyond a 

 question that individual feathers do change color. Most 

 of them are already pure white excepting the shafts of 

 the six outer primaries, which, as usual in winter speci- 

 mens of Lagopus albus, are black. The quantity of 

 black varies greatly in the different wings. In those in 

 which the change is most advanced it is merely a nar- 

 row strip of pale sooty-brown, extending along the 

 middle of the upper surfaces of the shafts of the six 

 outer primaries, and is confined to the middle half of 

 the exposed part of each, so that the basal half, and a 

 considerable apical portion, together with all the rest of 

 the wing, is pure white/' etc. 



Mr. Witmer Stone called my attention to specimens 

 of Terpsiphone cristata from Western Africa in the col- 

 lection of the Philadelphia Academy of Sciences, in 

 which an apparent transition of color of the tail without 

 moult is shown, but of an opposite character from the 

 instances above cited, viz.: from dark to light. The 

 tail in the first stage is colored a reddish brown or 

 rufous, this color changing to black, and the black to 

 white, apparently without any moult. In the orioles 



* Auk. ii, pp. 202-203. 



