25 
Mr. Henry Le Keux on the Turnip Fly. 
the fields lying to the north-west, and the turnips on the north- 
west side of the field were so destroyed by the fly that nearly an 
acre was quite bare, whilst the south-east side was not attacked in 
any perceptible degree until after the plants had attained to such 
a size as not to be much injured by their depredations. This cir- 
cumstance led me to conclude that the fly had been attracted by 
the scent, which subsequent observations have confirmed. When I 
became familiar with the form and character of the insect, I very 
soon found that its locality was not confined to turnip fields, but 
that it was to be met with in grass lands which had not been 
ploughed for many years, and where no turnips were to be found 
within half a mile. I have since found them in abundance in dry 
situations in all grass lands where I have taken the trouble to 
search for them. Although I found the insect in such abundance, 
I was unsuccessful in my endeavours to discover its mode of breed- 
ing until after five years, when a small piece of land (the upper 
part of a field sown with barley) in a sheltered situation with a 
south aspect, and which had been well dressed with lime, was sown, 
early in May, with white stone turnips for the table, but they no 
sooner appeared above ground than they were destroyed by the 
fly ; it was then sown again and harrowed, and the surface thickly 
strewed over with wood ashes, but the plants were again devoured 
as rapidly as before, and not more than a dozen acquired the 
rough leaf, and a few of these survived till the leaves grew to be 
six or seven inches in length, but they were perforated in every 
part. Upon examining one of these leaves (a portion of which, 
preserved dry, I send with this paper) against the light with a 
magnifying glass, I perceived a larva between the upper and under 
surface, a careful inspection of which led me to think it the larva 
of a beetle, and probably of the one I had been so long in search. 
I hastened back to the field, and carefully removed the earth 
around the plant from which the leaf had been taken, and there 
had the satisfaction to find the specimens of the larvae and pupae 
which I sent to my friend Mr. Raddon, who did me the favour 
to transmit them to the Entomological Society. 
I had previously endeavoured to breed them by keeping a num- 
ber confined in a small box covered with gauze wire, but as I 
could in this way only feed them by dropping in fresh bits of turnip 
leaf daily, I did not succeed in my object, although the insects ap- 
peared healthy, and I kept them alive in this manner from July 
until February in the following year. The reason of my failure is 
now sufficiently obvious, since it is necessary that the leaf should 
be in a growing state, otherwise the eggs which are laid upon it 
