INSECTS INFESTING WHEAT. 



279 



Fig. 264. 



each puncture. These eggs soon hatch into minute foot- 

 less, yellowish grubs, whose presence in the plant near the 

 joint soon causes the latter to swell, forming a sort of gall 

 which is of a hard, woody texture. These grubs remain in 

 their cells in the center of the stalk all Winter, and are 

 changed to Hies in the following Spring. The perfect insect 

 (Fig. 2(34) is wholly black with the exception of the front 

 shanks (tibite), which are pale yellow. 



Fig. 264. — Joint Worm 

 Flies, enlarged — color, 

 black ; a, the female ; e, 

 her abdomen, still more 

 enlarged ; c, her antenna, 

 highly magnified ; h, the 

 male fly ; /, his abdomen ; 

 d, his antenna. 



An insect very closely 

 related to the preceding 

 infests rye in the same 

 manner as the latter in- 

 fests wheat. This is 

 known as the rye fi^^ 

 {Earytoiim secalis — Fitch). It is wholly l)lack except the 

 front and hind shanks (tibia?), which are pale yellow. 



Two otlier species infest barley in the same manner as the 

 above insect infests rye. These are the black-legged barley 

 fly {Eurytoma hordei — Harris) — of a black color, with only the 

 knees and feet pale yellow ; and the yellow-legged barley fly 

 (Eurytoma favipes — Fitch) — of a black color, with all the legs 

 pale yellow. Some autliors contend that the four species of 

 flies described above are but varieties of one species, which 

 was first described by Dr. Harris under the name of Eurytoma 

 hordei. 



Remedip^s. — Use Xos. 56 and 20. 



