injurious insects. 251 



Its natural enemies. 



One of the most effective natural destroyers of the wheat-fly, is 

 undoubtedly our common yellow-bird {Fringilla irislis, 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). I am 

 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 inspeclion 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 lap 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 I 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 ChalcididcB ; 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 

 VOL. II. — no. II. K 



