affecting the Corn- Crops. 
485 
some of the wheat, examined it, and found in most of it a small 
larva or caterpillar alive; but in some it was already changed into 
the chrysalis state. 
" Being exceedingly anxious to determine the species of this ap- 
parently destructive animal, I planted some of the diseased roots in 
my garden under a handglass, where they flourished very much, and 
threw out strong shoots on each side (the middle shoot withered) ; 
but whether the flies escaped through some hole in the glass, or 
whether they were devoured by a colony of ants which made their 
nest under the glass, I cannot tell, as I did not succeed in this 
attempt, for when I pviUed \x\) the wheat, and examined it, there 
was an empty chrysalis in each plant. However, I had better 
luck in my next attempt : I placed several of the diseased roots of 
the- wheat in a small flower-pot filled with bran, and covered it 
over close with gauze, in such a manner that no insect could get in 
from the outside, nor could any escape from within, On the 14th 
of May three small flies were discovered sitting on the inside of 
the gauze. A few days after, three more of the same flies appeared. 
There were in the flow-er-pot of bran six roots of diseased w'lieat, 
which produced six flies. On examining the roots afterwards, I 
found an empty shell of the chrysalis in each, so that, I think, 
there can be no doubt of the identity of the insect in question. 
" I mentioned that the larva and chrysalis were always found 
deposited on the principal stem, jast above the root. This stem 
it invariably destroyed, which gave the crop a most disastrous 
appearance, so that there was scarcely a hope of any produce : but 
after the larva had changed into its chrysalis state the mischief 
ceased, and the root was not so materially injured as to prevent 
its throwing out fresh shoots on each side, or stocking itself, as the 
farmers term it, as I experienced by those W'hich I planted in my 
garden. 
" In short, at harvest-time 1 was most agreeably surprised to 
find a good crop of wheat, and the ears large and fine throughout 
the whole field. My friend thinks it the best crop on his farm, 
and supposes he shall have about three quarters and a half of 
thrashed corn from each acre. 
" The kind of wheat sown was a white wheat, lately inti oduced 
here from Surrey : my friend could not recollect with certainty its 
name, but thought it was called white Zealand wheat. None but 
what was sown early, about the latter end of September or the 
beginning of October, was affected by this insect ; and in one 
field, where a part of it was early sown with white, and the other 
with red wheat, at the same time, the white wheat was much 
affected, and the red but very little. The reason why the early- 
sown wheat only was affected is, I should imagine, because the 
cold at the approach of winter destroyed the fly before the late- 
2 K 2 
