19 
Irs NATURAL ENEMIES. 
One of the most effective natural destroyers of the wheat-fly, is 
undoubtedly our common yellow-bird (Fringilla tristis, Lin.) Fields 
much infested by the insect, have been for many years recognized 
even by passers on the highway contiguous to them, by the rough 
and ragged aspect of the heads of the grain (Plate 5, fig. c). Iam 
not aware that the cause of this peculiar appearance has ever been 
stated in any of the communications that have appeared in our 
agricultural papers. It results from the operations of this bird. 
Alighting, it adroitly grasps the wheat-stalk just below the ear, and 
clinging fearlessly to it, even when swayed to and fro by the wind, 
it with its bill parts down the chaff from the grain, and one after 
another of the worms to which it thus gains access are rapidly 
picked off and devoured. Thus several heads are generally freed 
from the worms, ere its repast is completed. That it is the worms 
and not the grain that it is in pursuit of, is readily ascertained by 
an inspection of the heads after the bird has left them : many of the 
kernels, not being sufficiently loosened to drop to the ground by the 
operation, will be found remaining, the maggots that were upon 
them only having been removed ; whilst those kernels of the head 
which are not infested by the worm, are passed over untouched. It 
is curious that this little creature, by a tap with its horny bill, or 
some other process, is enabled to distinguish those scales of chaff 
which conceal so minute a worm, from those which do not; a 
knowledge which we only arrive at when we have parted down the 
chaff. A flock, numbering about fifty, embracing both male and fe- 
male birds, appeared to make the field which I examined on the 
16th of June their constant resort, for a period of three weeks or 
more, where they could be seen busily occupied almost constantly 
every day. The number of worms consumed by them during this 
time must have been immense ; and [ cannot but believe that this 
lovely bird will henceforward be esteemed for its utility, as much as 
it has heretofore been for its beauty. 
I have as yet found but one insect parasite, which I am well 
assured subsists upon and destroys the worm of the wheat-fly. It is 
a hymenopter of the family Chalcidide ; but my acquaintance with 
the details of its history is as yet too limited to attempt an account 
of it. I shall be much disappointed if I do not meet with still other 
