44 



FLIES. 



a weight of earth put on it, somewhere about as much 

 as if at least thirty or forty yards deep of earth were 

 l^laced on one of ourselves, it is very unlikely that, 

 where it is not specially supplied with powers for 

 piercing the ground, it will come up again as a grub ; 

 and the Gnat-Midge, if it does develop, certainly can- 

 not make its way through. 



This is one of the points that show us how to keep 

 insects in check ; we need often merely to consider 



Fig. 40. — Hessian Fly, nat. size and magnified. 



just what is before our eyes and act on it. Once 

 down, and left down (for, of course, if we bring the 

 grubs up again by a second equally deeji plougliing we 

 lose our labour), we have in all probability buried the 

 coming attack safely away. 



All measures which will lessen the amount of couch- 

 grass, or other wild grass (in which it either is known 

 or believed, to lie in the heads, or shelter at the roots 

 during winter), would help to keep the amount of this 

 Midge in check. Clearing and burning rough grass 

 by hedge-sides is one method ; gathering up the corn- 

 stubble and burning it, directly the corn is harvested, 

 gets rid of whatever is at the roots ; and also (and this 

 is very important) all tJie dust from the threshing-ma- 

 chine shoidd he burnt wlierc reheat is knou'u to he at all 

 infested. The Bed Maggot may often be seen in 

 millions in this, and absence of attack has been found 



