1904.] TWO SPECIMENS OF HYBRID GROUSE. 413 



represented by white ones of the same kind, which become more 

 conspicuous through contrast with the black than the brown 

 is in the Blackcock. On the rump of the Riporre, however, the 

 brown of the feathers is substituted by white only at their edges, 

 while otherwise the fine wavy brownish lines remain. The upper 

 tail-coverts are black but have broad white edges, and so have, 

 although to a less extent, the middle i-ectrices. In the latter the 

 white edges are exaggei'ations of the conditions found in the 

 immature Blackcock ; in the former the white edges coi-respond 

 to the freckled edges of the same feathers in the Blackcock. 

 The tail of the Ripoire is deeply cleft, so that the middle recti'ices 

 are 2|-3| cm. shorter than the outer. The wing-coverts look 

 almost all white, but a closer examination reveals that their 

 basal hidden parts are black, or at least densely sprinkled with 

 blackish. The white in these feathers has a distribution which 

 corresponds to the area of the same feathers of the Blackcock, 

 which is freckled with buff. The ends of the secondaries of the 

 Rippore are more broadly tipped with white than in the Black- 

 cock. But otherwise these parts are blackish, richly mottled 

 with white all over their middle and basal portion. This is the 

 more pecviliar, as these parts of the secondaries ai-e pure white in 

 the Blackcock as well as in the Willow-Grouse. Here is thus a 

 characteristic which is not inhei-ited from either of the parents 

 as it appears at first, but it is nevertheless a tetricid charactei-istic. 

 The secondaries of the Blackcock ai-e, between the white basal 

 half and the terminal narrow white edge, blackish, more or less 

 mottled with buff. This area has, in the Riporre, expanded over 

 the greater basal part of the feathers at the same time as the 

 mottling became white instead of buff. In such a way the Riporre 

 lost the, for the Blackcock, charactei'istic broad white band across 

 the wing, while the narrow terminal band became broadened. The 

 outer web of tlie primaries, which in the Blackcock is pale 

 brownish with whitish mottling, has in the Riporre become 

 wholly white, and the inner web has in the latter become mottled 

 with white and quite white at the tips, where the Blackcock 

 shows a mottled area. 



A broad band through the eye of the Riporre is white. In 

 the same place the immature Blackcock, or that in summer 

 plumage, is mottled with white. Below this space the Riporre 

 has a black band in which the feathers are very feebly edged 

 with white. The same area is in the Blackcock glossy bluish 

 black, but immature males often show the same whitish edging, 

 although still less developed. The fore-neck and the sides of 

 the neck, as well as the chest and belly, of the Riporre are white, 

 although the invisible basal parts of the feathers are more or less 

 black. The upper part of the breast is black, but mixed with 

 broadly white-edged feathers. The feathers of the flanks are 

 black, with broad edges or outer halves white, whei"eby a spotted 

 appearance is produced. The lower parts have thus received 

 more white from the Willow-Grouse than the upper parts have. 



