CHAPTER OF CRITICISM. 
149 
him for the figure in Loudon), but I do not think it is by any means proved^ 
since kindred species, such as Pontia rupee $ and P. napi $ have been found 
in such situation at large, and not‘‘under glasses” (as Mr. B. mentions), also 
P. cardaminis $ with P. napi S'-. Mr. Haworth likewise mentions (p. 144), 
“ Spilosoma lubricipeda and menthrasti being united, and suspects urticce to be 
the produceand Mr. Schuckard found an Osmia and Chelostoma^ of two 
different genera, in company, which shows that some caution is necessary in 
determining species. 
I am, sir, &c., 
James C. Dale. 
Glanvilles Wootton, April 25, 1837. 
^The Sense of Smell in Carrion Birds-. 
To the Editor of the Naturalist. 
Sir, —My brother s paper on the sense of smell in carrion birds (p. 34) is con¬ 
clusive as far as regards that species or genus of which it treats; but I think 
there are probably great modifications of the sense in different birds, as we know 
to be the case in Dogs. I mean that those birds which live on carrion probably 
have it much keener than those which catch their prey alive, as all the Hawks, 
Falcons, &c. I think that Hawks [Query, the Falconidce ?— Ed.] hold the same 
place in the feathered race that the Greyhound does among Dogs; and the Crows, 
Vultures, &c., correspond to Fox-hounds and Harriers, which hunt by the scent, 
I am, sir, yours, &c., 
Beverley R. Morris. 
Dublin.^ April 19, 1837. 
One or two Criticisms. 
To the Editor of the Naturalist. 
Sir, —In the Magazine of Zoology and Botany^ Mr. Duncan supplies a paper 
which professes to give the characters and descriptions of the Dipterous insects 
indigenous to Britain, intending, I suppose, to mention all the species. In the 
genus Oxycera., however, he describes but six species, while in Mr. Curtises 
British Entomology for January and February 1833, no less than ten are included. 
I am aware that one of these, Oxycera afiinis^ may possibly be only a variety of 
0. muscaria ; but even supposing that to be the case, there remain three species 
of which Mr. Duncan takes no notice. Now Mr. Duncan either had seen 
Curtis's splendid work, or he had not. If he had, I am at a loss to find any 
excuse for such an omission; if he had not, he ought never to have attempted 
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