1904.] TWO SPECIiMENS OF HYBRID GROUSE. 415 



Willow-Grouse, and that in these hybrids the teti'icid inheritance 

 from the mother dominates, and probably becomes more so with 

 age. 



A similar conclusion is deduced from a study of the female 

 Rippore specimens. The darkest specimen in Upsala looks 

 almost like a small Grey-hen * which has got white or white- 

 freckled edges to her feathers. The proximal secondaries are, 

 however, like those of the male Riporre just described, and the 

 distal ones are wholly white. Another difference is that the 

 outer tail-feathers ai-e black. Towards the centre of the tail the 

 rectrices become more and more ti'ansversely (corresponding 

 to the i^ufous bars of the Grey-hen) mottled, first on the outer 

 web, then right across with whitish, then bufi" and rufous-buff, 

 so that the central tail-feathers are almost like those of a 

 Grey-hen, although the rufous bars are somewhat broken. The 

 white tips, absent in the outer tail-feathers, become larger 

 towards the centre. The outer tail-feathers ai-e thus more like 

 those of a Willow-Grouse ; the central ones more like those of a 

 Grey-hen. In addition to the white edges, the feathei's of the 

 back show another difference from those of the Grey-hen ; they 

 have, as a rule, only one or two rufous bars, the pi-oximal 

 of which is more or less broken, while the Grey-hen has three or 

 more. This difference in the Riporre is not, however, a charac- 

 teristic in which it approaches the Willow-Grouse, which has 

 numerous narrow wavy bars. The front of the tarsi is grey but 

 long- feathered. The claws are rather dark. The lightest of the 

 female Riporre specimens in Upsala has broader white-freckled 

 edges to the feathers on the back, but otherwise the same feathers 

 are almost similar to those of a Grey-hen with three complete 

 bars of buff. Wing and tail of this specimen are a little moi'e 

 freckled than in the other. The one has the abdomen white, 

 and is a young bird, while the darker is old. We have hei^e, 

 consequently, a. condition parallel to that above-stated for the 

 cocks, viz., the female Riporre becomes darker with age, and 

 resembles more a Grey-hen, and there is only one kind of Riporre, 

 the origin of which must be as stated above. 



EXPLANATION OF PLATE XXVI. 

 Hybrid Grouse, Lagopus lagopus S X Lyrurus tetrix $ . 



* The feathered toes, &c., prove the hybrid nature. 



