324 SYLVIID.K. 



with the throat entirely blue, received in 1823 from the eldest 

 Brehm (Beitrage, ii. p. 173) the name of Sylvia wolft. This 

 would appear generally to accompany the white-spotted rather 

 than the red-spotted form, and to it would seem to he referable 

 one of Capt. Hadfield's birds (Zool. s.s. p. 172). With this 

 possible exception, the Editor has no certain information as 

 to the occurrence in the British Islands of any but the red- 

 spotted form the true Ruticilla suecica, of which a male and 

 female are figured at the head of this article ; but, as there is 

 always a likelihood of the white-spotted bird, R. leucocyau, 

 finding its way to this country, he retains (on page 323) the 

 representation of it used in former editions of this work. 



In the ' Naumannia ' for 1855 (p. 166) Dr. Altum pub- 

 lished some observations which might at first sight appear to 

 decide the question at issue, and he accordingly thinks that 

 the supposed three species are but phases of plumage suc- 

 cessively undergone.* On the other hand, it must be re- 

 marked that a very considerable variation in the length of the 

 tarsus, commonly correlated with the colouring of the throat 

 in the males, is observable. Thus in jR. icolfi the tarsus 

 measures from *95 to 1 inch ; in 11. leucocyana from 1*04 to 

 1-08, and in the true 11. suecica from 1 to 1*18, thus shew- 

 ing that the entirely blue-throated birds on an average have 

 the shortest and the red-spotted the longest legs, while the 

 white-spotted form is intermediate in this respect. Further- 

 more, not only have, as already said, R. leucocyana and R. 



* In July, 1854, Dr. Altum bought a live Bluethroat, a young cock, then 

 having a dirty-white chin and throat, beneath which was a pale blue band bor- 

 dered with black across the upper part of the breast, and lower down the ordinary 

 reddish colouring. This plumage the bird kept till the beginning of March, 1855, 

 when the blue already existing gradually became deeper, through the wearing off 

 of the white edges of the feathers, and the narrow black border moie distinct, 

 while some blue feathers sprouted higher up on the throat. The original blue 

 now became day by day, clearer, and that which had just begun to appear, 

 broader, so that, on March 21st, it covered the whole throat except the chin and 

 a round spot of greyish-white in the midst. To his surprise, on the 23rd, he 

 found this spot grown reddish, so as to resemble the characteristic of the true 

 R. suecica (ctcrulecula, as he calls it) and two days later the whole breast was 

 blue, nearly as in R. wofjl. A week afterwards a clear white spot appeared, and 

 the bird was a perfect R. leucocyana. 



