Mr. Mankwick': Account, &c. : 
, 7 
the outfide, nor could any efcape from within, On the 14th of May 
three. {mall flies were difcovered fitting on the infide of the gauze. 
[See tab. 15. fig. d, D.] A few days after three more of the 
fame flies appeared; there were in the flower-pot of bran fix roots 
of difeafed wheat, which produced fix flies : on examining the roots 
afterwards, I found an empty íhell of the chryfalis in each, fo that 
I think there can be no doubt of the identity of the infeét in quef- 
tion. 
.. lmentioned that the larva and chryfalis were always found de- 
_pofited on the. principal ftem juft above the root, This ftem it- 
invariably deftroyed, which gave the crop a moft difaftrous appear- 
ance, fo that there was {carcely a hope of any produce: but after 
the larva had changed into its chryfalis ftate the mifchief ceafed, 
and the root was not fo. materially injured as to prevent its throw- 
ing out frefh fhoots on each fide, or ftocking itfelf as the farmers 
term it; as È experienced. by thofe which I planted in my garden.’ 
In fhort, at harveft time I was moft agreeably furprifed to find a 
good crop-of wheat, and the ears large and fine throughout the. 
whole.field. My friend thinks it the beft crop on his farm, and fup- 
pofes he fhal! have about three quarters and a half of threfhed corn 
_ from each acre, 
-~ I hope fome other gentlemen of the Linnean Society have had 
. opportunities of making their obfervations upon this fubje&. I do 
not pretend to any very great fkill in Entomology; I only relate 
facts, and have endeavoured to be very accurate in ftating them. 
During my obfervations upon this infect, a variety of thoughts 
fuggefted themfelves to my mind. It was hinted to me, that poffibly 
this was what has been called the Heffian fly, whofe depredations 
‘in America have been fo notorious. If fo, a little good Englifh huf- 
bandry, by keeping the ground in heart, and thus enabling the 
wounded fhoots to repair themfelves by ftrong lateral ones, prevents 
sur being alarmed to fo great a degree. I had my doubts how and 
E - what 
" 
