98 



INSECTS INJURIOUS TO STAPLE CHOPS. 



to one-half an inch in length. The smaller ones may not 

 have bored through a single joint; while the larger ones 

 will have tunneled all of them, except, perhaps, the one 

 next to the ground. 



Life-history. — "As the grain becomes ripe the larva 

 works its way toward the ground; and at the time of 



Fig. 59. — The Wheat Saw-fly Borer {Cephus pygmrfus Linn.), n, 

 outline of larva, natural size; h, larva, enlarged; c, larva in 

 wheat stalk, natural size; d, frass; e, adult female; /, Pachyo- 

 nerus calriir-itor, female, a parasite — enlarged. (After Curtis, 

 from "Insect Life.") 



harvest the greater number of them have penetrated the 

 root. Here, in the lowest part of the cavity of the straw, 

 they make ^^reparations for passing the winter, and even 

 for their escape from the straw the following year. This 

 is done by cutting the straw circularly on the inside, 

 nearly severing it a short distance, varying from one-half 

 to one inch, from the ground. If the wheat were growing 

 wild, the winter winds would cause the stalk to break at 



