RS — ————— 
| work of destruction. 
706 
of twenty; and they amount in the aggregate to 
so vast a multitude as might seem to threaten 
terrible desolation or even utter destruction to 
wheat crops. They are oblong, transparent, and 
of a pale buff colour; and are hatched in the 
course of ten or fourteen days. ‘The minute 
maggots which proceed from them have the 
same general form as other dipterous larve ; 
and are at first transparent and colourless, 
but soon begin to assume hues of straw-co- 
lour, yellow, saffron, and orange, according to 
their age. They are thought by some persons to 
feed on the pollen, and by others to live on the | 
juices of the ovary; and they not improbably de- 
vour the reproductive substances of both the an- 
thers and the germen, both before and after the 
shedding of the pollen; but at all events they so 
completely destroy the reproductiveness of the 
particular florets in which they are lodged that 
_the seed never forms and the parts of fructifica- 
tion lose all their virus and shrivel and decay. 
So many as forty-seven have been counted in 
one floret; and even the smallest number ever 
present seem to be perfectly competent to do the 
Nearly all become full- 
grown about the beginning of August; and they 
_ may then or a little earlier be easily found on 
_ examining an infested ear; and they afterwards 
either remain among the heads of the wheat, and 
continue ensconced there till they become trans- 
formed into pupa, or leave the ear, and pass 
_| down to the ground, and bury themselves in the 
| soil or about the roots of the stubble, there to 
| await their transformation ; and when the corn 
is thrashed, either the larvee themselves envelop- 
ed in a singular kind of membrane, or the pupze 
which have been formed from them, may be dis- 
covered in the chaff-dust, and if abundant and 
conspicuous, will readily be mistaken by unsus- 
pecting farmers and farm-servants for the seeds 
of weeds. “Naturalists who have given their 
attention to these insects,” says Mr. Sidney, “are 
of opinion that the chrysalis state is not reached 
till the spring, and that the thin membranous 
covering is a protection against cold till that con- 
dition is attained. It is true that there has been 
one instance of a fly hatched from a chrysalis in 
September, but this was an exception. There 
have been many attempts made to breed these 
flies from the larve covered with the membrane, 
or the supposed chrysalides found in the chaff; 
but all have failed. It was tried in vain by the 
writer; but he thought others might have ob- 
tained them by reason of more skilful methods, 
till on inquiry he found they were equally un- 
successful. Conjectures have, as usual, been suf- 
ficiently abundant; and a question has been 
raised, whether the larvee do not enter the earth 
to become pupe or chrysalides. Certain it is 
that the membranous cases of the larve are 
found left adhering to the sound grains and to 
the chaff-scales; and Professor Henslow and 
others assert, that some larve have been known 
WHEAT-FLY. 
to leave the ears and bury themselves in the 
earth. Any entomologist who decides the ques- 
tion whether these larve certainly enter the 
ground to turn into pupe, will do great service 
to science in general, besides affording informa- 
tion to the farmer respecting the habits of one 
of the most fatal enemies to his produce when 
the season is suitable to them.” 
The ravages of the wheat-midge are somewhat 
fitful,—insignificant in one season and excessive 
in another,—inconsiderable on some farms or 
crops and very considerable in others; but, in the 
aggregate of years, they are much greater than 
most farmers are aware of or would readily be- 
lieve. Mr. Kirby estimated the loss in a field of 
15 acres which he particularly examined at about 
one-twentieth of the whole produce, or at an 
average of about two grains in each ear. Mr. 
Markwick, who in the first instance did not sup- 
pose the wheat-midge did any serious mischief, 
became eventually convinced that Mr. Kirby’s 
estimate was not too high if applied to infested | 
wheat-crops in general; for of the ears which he 
examined, scarcely any contained fewer than two 
injured grains, most contained more, and some 
contained so many as six. Mr. Gorrie estimated 
the loss in the late sown crops in Perthshire, in 
1828, at one-third of the whole produce. Mr. 
Bell of Mid Lioch, writing in June 1830, ex- 
presses apprehensions respecting the crops of 
Scotland fully in accordance with Mr. Gorrie’s 
estimate, and says, “ Another year or two of the 
wheat-fly will make two-thirds of the farmers 
here bankrupts.” 
can assert that in the autumn of 1845, he found 
great quantities of the larvee not only in a first- 
rate wheat district in Norfolk, but in other parts 
of the country. Har after ear was gathered by 
him, examined, and the contents shown to far- 
mers who never before had even heard of such 
things, and who were perfectly-astonished when 
they saw them. Often has he also entered a barn 
and taken up a handful of dust from the floor 
where wheat has been winnowed, turned out the | 
little orange-coloured devourers, now in their 
membranous cases, one after another, but scarce- 
ly ever met with any person who had previously 
noticed them. If they had seen them, they took 
them for the seeds of some kind of weed. There 
seems also to be good reason to suppose that the | 
wheat-midge is to be found on the continent of 
EKurope, and that it attacks the corn-crops in 
France, causing the same sterility in the grains 
that has been shown to be the result of its ra- 
vages in England.” 
The wheat-midge is known tosubsist on common 
couch grass, 7reticwm repens or Agropyrum repens, 
in the same manner in which it subsists on wheat ; 
and it might therefore be supposed to attack 
with equal readiness all plants more nearly allied 
to wheat, and particularly all the species and va- 
rieties of wheat itself; yet it is generally believed 
to have strong preferences and dislikes in refer- 
Mr. Sidney says, “ The author | 
A EAI PATOL COE LORE SE” ETRE SIN NE ISTO I SOPOT TS ITEP PESTLE SAE POC AS AIO APO ET AP or ere 
