228 MR. R. COLLETY ON HYBRID GROUSE.“ _—_[Apr. 20, 
about one diameter of the eye). In ZLagopus they are still shorter, 
or one diameter and a half, in 7’. tetrix one or two diameters longer 
than the central rectrices. 
Male and Female.—Besides the markings and size the following 
differences occur between the two sexes—the tail of the female is 
nearly square, the side branches of the upper mandible are more 
developed, and the comb-like scales of the toes and the ridge of the 
eyebrows are considerably longer in the male than in the female. 
Measurements. 
Male. 
Total ’ Outer tail- Centre tail- 
length. Wane feather. feather. 
mm. mm. mm. mm. 
1.... 470 242, 142 122 Gudbrandsdalen, 7 Dec. 1870. 
2.... 480 238 147 ey. Saltdalen, Nordland, 30 Dec. 1871. 
eit 237 138 106 Gudbrandsdalen, 8 Oct. 1872. 
4,... 508 255 142 125 Osterdalen, 5 Nov. 1872. 
5.... 480 252 140 2 Gudbrandsdalen, (?) Noy. 1872. 
6.... 499 245 2 130 Gudbrandsdalen, 28 Feb. 1875. 
Ufpere 0s: 232 146 124 Hadeland, 27 Dee. 1879. 
8.... 480 235 135 115 Tolgen, 3 Nov. 1881. 
Cease eesele 235 140 118 Sande Pred, 9 Noy. 1881. 
10.... 530 235 150 125 Roros, 10 Oct. 1882. 
Female. 
11.... 423 205 127 97 Gudbrandsdalen, Jan. 1875. 
12.... 425 205 118 100 Roros, 7 Oct. 1876. 
It will be seen from these measurements that the male has an 
average length of 490 millim., about equal to that of the female Tetrao 
tetrix (but with slightly longer outer tail-feathers). ‘The total 
length of the female is about 424 millim., being thus considerably 
less than the male; it is, however, somewhat larger than the male 
Lagopus albus. 
Colouring. 
Of the fourteen specimens of this hybrid at present preserved in 
the Museum at Christiania, one is a young bird of the year, on 
which the brown plumage almost entirely remains; four are young 
birds changing to winter plumage, the latter being predominant ; 
finally, are eight in full winter plumage, and amongst these are two 
females. Besides these there is one specimen (a male in winter 
plumage) exhibited as a skeleton, 
In winter plumage are also the specimens in the Bergen and 
Upsala Museums. The specimens at Stockholm are likewise, so 
far as is known, in winter plumage, or in the changing from autumn 
to winter. A long link in the series is entirely wanting in all 
these collections, namely—the spring plumage, which is probably 
unknown ; the summer plumage, which is in all cases known from 
