450 
THE TURNIP-FLY. 
sorts of greens are growing all around them.” They are also to be 
found, throughout the Summer, in grass fields, and indeed, in all 
fields where vegetation is found. Mr. Henderson says, “ there are al¬ 
ways great numbers of these insects to be found throughout the Sum¬ 
mer among the grass; with a net, such as is used for catching cele- 
opterous insects, thousands of them may he caught any fine evening 
from May till October, by merely brushing the tops of the grass.” 
Mr Godfrey Wright states, he has found them amongst the wheat 
crops whilst weeding. Dr. Fleming also states, they are found in oat 
and barley fields, and feed upon the wild mustard and wild radish. 
There can be no doubt but many other wild growing plants form the 
food of the insect, and that it is not dependent upon the cultivation 
of turnips for its food. 
Mr. Henderson has also found that the insect, after arriving at its 
perfect state, increases considerably in size: those, which he observed 
for a length of time upon the turnips in the garden, were, in August, 
much larger than when they first appeared; and considerably larger 
than those, which in the same month, were to be found in the grass 
in the park. The latter were of various sizes, but the greater num¬ 
ber of them very small. This leads him to the conjecture that the 
insect may be bred amongst grass. 
In the Entomological Magazine for July, 1833, is an article 
signed—“ Rusticus” and dated at Godaiming, in which experiments 
are detailed to prove that the insect is produced from an egg deposited 
on the seed of the turnip. The writer dates his experiments so far 
back as 1823, and that his subsequent experience has confirmed his 
opinions. See Hort. Reg. Vol. 2 page 377. 
No opinion is more common than that the insect springs imme¬ 
diately from an egg into a perfect fly ; and that the exposure of the 
egg, by ploughing and working the land, is the more immediate 
cause of its vivification. Upon this hypothesis Mr. John Sutton, of 
near Salisbury, adopted the plan of preparing the fallows for the seed, 
and leaving the land for ten days or a fortnight before sowing; in 
which time he concluded the fly would be hatched and die for want 
of food. This plan he, after trial, published in a pamphlet, and it 
has obtained considerable celebrity, and has still many partisans. In 
our returns its success is in many instances stated ; although in 
others also its failure. But it is certain, some considerable measure 
of success must have attended the plan, whatever opinion may be 
held of the hypothesis upon which it was founded. The eligibility 
of the plan will be hereafter considered ; but, as far as it bears upon 
the natural history of the insect, we must here remark, that it can by 
