3 10 CORRESPONDENCE. 



has a darker and more permanent foliage, and is a handsomer tree, the wood is 

 smoother, the fibres are less tortuous, and the medullary rays are further apart than 

 in Q. pedunculated. From some prejudice or misrepresentation, the former tree 

 alone is supposed to afford good timber, and thus the handsomer, quicker-growing 

 Oak is seldom planted. I am not aware of the precise difference in their rate 

 of growth, but I have the authority of Professor Lindley for stating that it is 

 very great. Were this fact generally known it might be an inducement for 

 planters to grow this species of Oak. 



I remain, Dear Sir, 



Your obedient servant, 

 Campsall, near Doncaster, Edwin Lankester. 



July 19, 1837. 



On the Turnip Fly. 



To the Editor of the Naturalist. 



Sir, — I beg leaTe to suggest, through your pages, to such of your readers as 

 may have time and opportunity, the propriety of watching the habits, &c, of the 

 " Turnip Fly" in their various neighbourhoods, as I begin to suspect that there 

 are at least three species of insects which have a hand in the destruction of our 

 Turnip crops ; each, however, being confined to its own locality, and not fre- 

 quenting the districts infested by the other. One of these is Athalia spinarum, 

 on which there is a paper by my brother, the Rev. F. 0.- Morris, at p. 180 of 

 Vol. I. This, I think, is the only one known in the south of England. The 

 next is, I believe, an Aphis, but what species I have yet to be informed, as I 

 have never myself seen it. It was mentioned to me by Mr. C. Storer, of 

 Hawksworth, Nottinghamshire, who says that the Turnips in that neighbour- 

 hood were infested by a small fly which, from his discription, I take to be an 

 Aphis. He says the leaves turned yellow, no doubt from their juices being 

 extracted by these insects. The rain did not appear to affect them, as they 

 were chiefly on the underside of the leaf. He observed them one evening, late 

 in September, in immense swarms in the air, near his residence ; in such num- 

 bers indeed were they, that they might be taken in handsful from the windows 

 on which some few (! ) of them settled. He did not at all know the larva of 

 Athalia spinarum on my describing it ; so that I imagine the Turnip Fly of that 

 district must be a very different insect from that of the South of England. The 

 third is a Haltica, but how it commits its ravages I do not know, unless it be in 

 the early stages of the growth of the seed, or on the seed itself before germina- 

 tion ; it could, I imagine, do but little injury to the full-grown plant. I should 

 be glad if any of your correspondents would give me their experience on the 



