5162 THE ZoOLOGIST—NOVEMBER, 1876. 
rubicola (indica), Parus borealis (Kamschatkensis) have, as with most 
continental forms, a tendency in the opposite direction—towards a mealier 
phase or plumage? Actual melanism is caused, in some instances, by 
particular kind of food, especially in caged examples. In a state of nature 
also may not the same be caused by the superabundance of some particular 
kind of food to which the species, or perhaps certain individuals of a species, ' 
are specially partial. I wonder if feeding on mosquitos makes the sand 
martin black or dark-coloured in North Russia !—I know they made the 
unprotected faces of our captain and his mate very red by feeding on them 
in the space of a very few hours. Generations of sand martins constantly 
feeding on mosquitos may, by a process of gradual poisoning, have become 
changed in appearance, as people become who eat arsenic. When projecting 
a trip to Persia—which, however, was not undertaken—I was asked to 
bottle as many of the poisonous bugs of the country—I forget their name— 
as I could, by a chemist who desired to analyse the poison. Has anyone 
ever analysed the poison to be found in specimens of Rae's Culex damnabilis 
(vide Rae’s ‘Land of the North Wind’)? Possibly, if it could be done, some- 
thing sufficiently strong to turn people's faces black—let alone little birds 
like sand martins—would be discovered. Your readers may adopt the above 
theory or not, as it suits their own ideas; but my opinion, at all events, 
is that Rae’s name should have priority. I do not wonder at the sand 
martins—poor little things!—getting black. —John A. Harvie Brown; 
Dunipace House, Larbert, N. B., October 16, 1876. 
Golden Eagles trained to capture Wolves and Foxes.—In ‘ Nature’ for 
August 24, there is an extract from a Jetter by Dr. Finsch, who, together with 
Dr. Brehm and Count Waldburgzeil, is at present engaged in the scientific 
exploration of Southern Siberia, under the auspices of the German Arctic 
Society. The letter dates from Lepsa, near the Balkash Lake, May 18, 
and the following occurs in the extract:—‘ Numbers of Argali were seen 
running on the mountains, and we proposed for the next day an Argali 
hunt. The hunting party offered a strange picture on the next morning; 
there were fifty Kirghiz chiefs on horseback, many of them holding golden 
eagles on their hands. ‘These birds are trained here to catch the wolf and 
fox, and they acquit themselves excellently of their task, except in spring, 
when, their minds being taken up by love-thoughts, they are unfit for 
work.” May I enquire if the training of golden eagles to hunt has ever 
been successfully tried in this country, or if these fine birds are educated 
by man to capture wolves and foxes in any other portion of the globe?— 
R. M. Barrington; Fassaroe, Bray, County Wicklow, September 13, 1876. 
[Several such instances will be found mentioned in Mr. Harting’s 
‘ Ornithology of Shakespeare,’ pp. 36, 37.— Eb. ] 
Goshawk in Lincolnshire—The goshawk (Astur palumbarius, Linn.) is 
now so rare a visitant to our shores that any occurrence is worth putting 
