17s CALIFORNIA ACADEMY OF SCIENCES. 



apparently vestiges of some former color of the bird. 

 This under color is of no more utility than a rudimen- 

 tary organ. A good illustration of this class is presented 

 by the feathers of the black throat patch of the meadow 

 lark {Sturnella xicujnit). These feathers generally have 

 a white basal portion and a black terminal portion, with 

 a more or less decided tinge of yellow upon the white 

 nearest the edge of the black. This is plainly a relic of 

 the time when the breast was all yellow, for only the 

 black is now visible, and the white and yellow bases 

 could be of no possible utility. These feathers are 

 very common in patches of bright color, as the scarlet 

 head of the Californian woodpecker, where the feathers 

 are black below the scarlet. It is interesting to note 

 that the extent and distinctness of the subterminal line 

 line of black on the scarlet feathers decreases in orderly 

 succession from the feathers of the frons backward 

 toward those of the nape. This is directly parallel with 

 the extent of the scarlet on the head of the different 

 forms now living. The scarlet in these decreases and 

 the black increases from the frons backward. In gen- 

 eral, it may be said that true hybrids occur only along 

 the border line of two color areas, while pseudohybrids 

 are sometimes the only form found throughout an entire 

 color patch. 



There is but one other form of psevidohybrid to be 

 considered and this an uncommon variety. In the red- 

 winged black birds the line of division of white and 

 scarlet upon the shoulder is made by the scarlet feathers 

 overlapping the white. In other words, there are no 

 true hybrids. Frequently in Agelalns tricolor an infu- 

 sion of pink or bufiy is noticed upon the white feathers 

 as if some of the scarlet pigment had run in upon the 

 white by mistake. A. gubernator frequently has a blush 

 of scarlet upon the buffy feathers. 



