TURNIP-FLY. 93 



Schemes out of number have been tried to get rid of or 

 kill this little pest wherever it has appeared, the particulars 



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 breeding until after 

 five years, when a small piece of land (the upper part of a field sown with bar- 

 ley) 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 ta- 

 ble, 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 sur- 

 vived 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 magni- 

 fying 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 of. 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 specimens of the larvae and pupae. 



" I had previously endeavoured to breed them, by keeping a number con- 

 fined in a small box covered with wire gauze, 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 appeared healthy, and I kept them alive iu 

 this manner from July until February in the following year. The rea- 

 son 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 shrivel up when the leaf becomes dry. Being still at fault as 

 to the origin of the larvce, I captured ten males and ten females in pairs, 

 and inclosed them in a glass tube covered at each end with wire gauze, 

 into which I introduced a single leaf of turnip, with water to keep it 

 fresh ; by this means I was enabled to examine the insects and leaf on all 

 sides with a magnifying glass at any time without disturbing them. Hav- 

 ing, previous to introducing the leaf, ascertained, with a strong magnifyer, 

 that there were no eggs or larva? upon it, on the following day I had the satis- 

 faction to perceive five small, smooth, oval-shaped eggs adhering to the un- 

 derside of the leaf, and so nearly resembling it in colour that I was no longer 



