of Gmelin’s Edition of the Syf. Nature. 8x 
Banks, I find that they are not uncommon, having frequently 
found them in autumn on-umbelliferous plants; and infeéts of this 
order feldom live fo long in their perfect ftate, and are rarely feen 
abroad fo late in. the year as the latter end of October: indéed, if 
there are two breeds in the year, a queftion will arife, upon what 
plant is the fecond brood nourifhed? for wheat fown the latter end of 
September, or the beginning of October, muft be fome time before 
it appears above ground. And yet I cannot believe that the egg is 
carried there either by manure or by any other means than by the 
parent fly, from this fingular property, that only one latva is found 
on each plant, and that always in the principal ftem; for. although 
the Mufcæ in general depofit a number of eggs in one fpot, it is 
always where plenty of food is at hand to nourifh the young larvæ 
immediately on their being hatched. I am therefore defirous to 
offer the following hints for obfervation, hoping that fome gentle- 
man will take up the fubject, and examine it ftill more clofely. 
When it appears evident that a fly has attacked a field of wheat, 
rye, &c. watch carefully the animal through all its ftages, but more 
efpecially when the fly takes wing, obferving on what plants it 
fettles, and whether it is partial to any particular plant; and if thia 
can be determined with precifion, attend to fee it depofit its eges, 
carefully examining whether it lays more than one at a time. If 
. afterwards the larvze appear on thofe plants, obferve in what man- 
ner they feed, continuing the remarks till the perfe& infect appears, 
when it muft be again watched with attention, and traced to its 
next place of depofiting its eggs, to determine whether wheat 
or rye be its natural food in fpring, or whether its attack on 
thefe plants be only in particular feafons when its own natural food 
may have failed ; for Mr. Markwick takes notice, that it was only 
the early fown wheat that was affected. 
From the ee obfervations of Mr. Markwick, that the 
Vo. H. - ; M dií- 
