22S NATURAL HISTORY. [cH. XV. 



The larvae are hatched in eight or ten days, when 

 they immediately comni.ence feeding upon the pollen, , 

 which is only sufficient, however, for their supply in 

 the first instance, after which they crowd round the 

 lower part of the germen, where they probably feed 

 upon the matter which had been destined to form 

 the grain. As many as forty-seven larvse have been 

 counted in a single flower, so that an idea may be 

 obtained of their minute size. 



It appears, moreover, that this little insect abounds 

 in some seasons to such a degree, that it destroys at 

 least one twentieth part of the crop. After arriving 

 at their full size the larvae quit the ears of wheat, 

 and fall to the ground, beneath the surface of which 

 they are transformed into pupae. At the period 

 when Messrs. Kirby and Marsham commenced their 

 investigations of this insect, three minute hymenop- 

 terous flies were observed prowling about the ears 

 of wheat, and it was afterw^ard discovered that some 

 of these flies were produced from the maggots found 

 attacking the grain; hence it became the general 

 opinion of unscientific persons, that these minute 

 flies were the parents of the maggots, and the origin 

 of all the mischief. In pursuing their investigations, 

 it was however discovered that these three diflferent 

 species of hymenoptera were parasites attached to 

 the wheatfly, and appointed by an all-wise Creator 

 to prevent their too great increase. 



While the wheat of our own island is thus subject 

 to the attack of one species of cecidomyia, it would 

 appear that that of America is ravaged to a far 

 greater extent by another species, to which the 

 name of the Hessianfly is given, and it has been 

 recently described under the name of Cecidomyia 

 destructor. This species attacks the young wheat 

 as soon as it appears above ground, and entirely de- 

 stroys the plant by eating into the stem, so as to 

 cause it to break. When it first made its appear- 

 ance in Long Island, in 1776, the devastation which 



