WHEAT-FLY. 
reasoning relative to the inferences people de- 
duce without accurate investigation, when they 
merely see two things together. Just in the 
same way some farmers have concluded that the 
little ichneumon flies we are now noticing must 
lay the eggs producing the larve of the midge, 
because they have themselves seen them amongst 
the corn containing these larve. It is time for 
all observers to arrive at a better state of know- 
ledge, lest we destroy, as authors of mischiefs, 
the friendly antidotes to their increase. Preju- 
dice and hasty judgment lead to perpetual mis- 
constructions as to things both moral and natu- 
ral, But to return to the ichneumon. This little 
platygaster may be readily found on the glumes 
of the wheat-plants, in the months of July and 
August. It runs rapidly over the ears, and 
seems to know well which are those occupied by 
the larve of the midge. The author found num- 
bers of them in various wheat-fields in August, 
1845 ; and almost invariably, on examining the 
ears on which they appeared, discovered that 
they contained the objects of their search. The 
ichneumon hunts for them with the utmost 
eagerness, and by the aid of a sharp tail places a 
single egg in each of their bodies. The sight 
has been witnessed by the following experiment: 
a number of larve of the wheat-midge were put 
upon a piece of white paper, pretty near each 
other, and an ichneumon was dropped into the 
midst of the group. The energy of her manner, 
the rapid vibrations of her antenne, and the 
whole of her attitudes, were most amusing. On 
approaching one of the larve, her agitation 
quickened to the utmost intensity ; she soon 
bent her body in a slanting direction beneath 
her breast, applied her tail to the larve, and, 
becoming still as death, sent forth her curious 
sheath and deposited her egg in the victim, 
which writhed considerably under the operation. 
If she came to one that had previously an egg 
in it, she left it in an instant and sought an- 
other; for the platygaster lays but one in each. 
This, however, often repeated, destroys a great 
many of these little devastators of the grain. 
The observations of Professor Henslow confirm 
those which have been already made. He says, 
‘ When these eggs are hatched, the young mag- 
gots which they produce, and which are the 
caterpillars of the ichneumons, feed upon the 
fleshy or muscular parts of the caterpillar they 
are attacking, carefully avoiding the vital parts. 
At length the caterpillar they have been thus 
devouring alive dies; or, as frequently happens, 
it changes to the state of a chrysalis before it is 
destroyed. The ichneumon caterpillars also pass 
to the chrysalis state, and either remain within 
the body of the dead caterpillar, or come out 
before they assume the fly state. Each species 
of ichneumon is restricted in its attacks to one 
or at most toa few particular species of cater- 
pillar; and the females instinctively proportion 
the number of eggs they deposit in each indi- 
LOD 
vidual to the relative size of their own offspring 
and that of the insect on which they are des- 
tined to prey.’ It is impossible to contemplate 
these habits of the minute insects thus brought 
before our notice, without being deeply im- 
pressed with the omnipresence of the great Be- 
ing to whom all things owe their existence. The 
same hand that spread the north over the empty 
space, and suspended the earth upon nothing, 
and keeps the stars in their courses, regulates 
the numbers, instincts, and uses of the smallest 
living things, appearing equally perfect in all: 
‘ What less than wonders from the Wonderful, 
What less than miracles from God can flow ?’” 
The American wheat-midge or Hessian _fly, 
Cecidomyia destructor, works great havoc in Ame- 
rica, and has of late years become known in 
various parts of Continental Europe, but does 
not seem to have ever been detected in Britain. | 
Yet it deserves somewhat particular notice, at 
once as an object of general curiosity to agricul- 
turists, and on account of its congenership to 
the British wheat-midge, and for sake of the 
possibility of its yet becoming practically and 
painfully known to the British farmer. “ The 
Americans,” says Mr. Curtis, “ entertain an idea 
that this fly was first introduced into their coun- 
try in straw which accompanied the Hessian 
troops; whence they have given it the appella- 
tion of Hessian fly. It has been occksionally a 
dreadful scourge in North America, for the lar- 
vee have committed such ravages on the wheat- 
crops as to cause even famine in the land. It 
was not until the autumn of 1833 that this de- 
structive insect, or a species closely allied to it, 
was observed in Hungary; whether, from its 
previous rarity, it had been overlooked, or had 
not found its way into the Austrian dominions, 
is not known. Kollar states that it appears, 
from a report transmitted to the Archduke 
Charles, that in the beginning of June the ears 
of wheat were observed to droop and the straw 
to bend, on his estates at Altenburgh, although 
the crop was previously in fine condition: ina 
few days, patches on the poorest soil in different 
parts became entangled, as if matted together 
by heavy rains or high winds, which were sup- 
posed at first actually to have been the cause. 
This soon proved to be unfounded; for the 
mischief gradually spread from the poor to 
the best lands, until the whole was blighted. 
Two-thirds of the straw at least was laid in less 
than a week, and the work of devastation was 
completed by the heavy fall of rain which took 
place during the latter part of June. The straw 
thus prostrated produced only small abortive 
ears; the few grains they contained were shri- 
velled, and would scarcely ripen, and the straw 
was of a very bad quality. On examining the 
roots of those plants which had died off, the soft 
straw where the larvee had stationed themselves 
in families, within the sheath of the leaf, ap- 
