■310 ■COBRESPON'BENCE. 
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. peduneulata. 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. 
Julp 19, 1837. 
On the Turnip Fly. 
To the Editor of the Naturalist. 
Sir, —I beg leave 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 Aihalia 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 Apkis^ hut what species I have yet to he 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 fete) (I) 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 he a very different insect from that of the South of England. The 
third is a Haltica^ hut 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 
