THE WHEAT MOTH. 131 



through the upper surface. Then somewhere on the 

 upper surface of the leaf it weaves a circular silken 

 covering about one-twelfth inch in diameter. Stretched 

 out on this network the larva, which is now about one- 

 tenth inch long, makes a small hole in it near its edge, 

 then, as one would turn a somersault, it puts its head into 

 this hole and disappears beneath the silken covering, 

 where it undergoes a change of skin. It remains in the 

 moulting cocoon usually less than twenty-four hours. 

 After leaving this cocoon it feeds upon the leaves without 

 making a mine ; and in a few days makes a second moult- 

 ing cocoon, which differs from the first only in being 

 about one-eighth inch in diameter. After leaving this it 

 again feeds for a few days, and then migrates to a twig, 

 where it makes the long-ribbed cocoon within which the 

 pupa state is passed. This very interesting life-history 

 was first worked out by Mr. A. E. Brunn, while a student 

 in the writer's laboratory at Cornell University. When 

 it is necessary to combat this pest the smaller twigs 

 bearing cocoons should be pruned as far as practicable 

 during the winter and burned, and those cocoons that 

 remain on the large branches should be washed with 

 kerosene or kerosene emulsion." 



V 



Prevention and Remedies. 



We have previously mentioned that nearly the whole 

 of these insects when in the larval stage are vegetable 

 feeders, so as to prevent the egg-laying, all the grass and 

 other herbage growing on headlands, or in the vicinity of 

 the cultivated paddocks, should be kept down by either 

 ploughing, burning, or by other means. It is a good plan 

 to sow strips, or belts, of any succulent plants which 

 would not be likely to become noxious weeds, such as 

 castor oil, larkspur, &c., both of which are hardy and of 

 rapid growth, and have the merit also of being deadly to 

 caterpillars eating the leaves. If possible, these strips 

 should be confined by fencing, so that cattle, horses, and 



