WHEAT INSECTS, ETC. 23 



fortunately for our country, their ravages are here unknown, 

 except by description. Oiu* wheat whilst in blossom suffers 

 from the attacks of the Hessian fly Cecidomyia tritici 

 and C destructor^ the larvae of which devour the pollen. 



Cecidomyia tritici and destructor. 



whilst its roots are devoured by the larvae of the Zahrus 

 gihhus, which sometimes, as in the year 1812, near Halle, in 

 Germany, is produced in such numbers, that whole corn 

 fields are entirely destroyed. The larvae of some of the 

 Elaterida, known by the ordinary name of wire-worms, also 

 attack its roots, as well as the roots of various other garden 

 plants and culinary vegetables. The grubs of the cock- 

 chafer in like manner often do much injury, by devouring 

 the roots of grass, as do also those of the Tipulce. Of the 

 former, an instance is recorded by Kirby and Spence, in which 

 all the fields of a farmer near Norwich were entirely destroyed, 

 and as many as eighty bushels of the insects were collected by 

 him and his men. Various other esculent roots are also de- 

 voured by the larvae of other insects ; amongst which the 

 damage occasioned by the onion-fly {Anthomyia ceparum), 

 the grub of which destroys the plant when still very young, 

 is perhaps the most obnoxious. In like manner the stems 

 and the pith of trees and plants are equally subject to the 

 ravages of insects, amongst which may especially be noticed 



