126 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



their wings, and scatter themselves about over fields adjacent to 

 their place of development, is shown by their occurrence in fields 

 of grasses (in the stems of which they do not breed) situated 

 considerable distances from wheat fields. In ovipositing, the 

 females of this generation select the largest and most vigorous- 

 growing stems in which to place their eggs. 



" The adults of the second generation deposit their eggs 

 from early May, in Texas, up to the middle of June, in northern 

 Indiana, or about the time the wheat is heading. Their aim 

 at this time is to place the eggs singly in the growing stem, 

 just above the youngest 

 and most succulent joints, 

 which are not so covered 

 by the enfolding leaf 

 sheaths as to be inaccessi- 

 ble to them. Thus it is 

 that the stage of advance- 

 ment in the growth of the 

 wheat stem at the time of 

 oviposition of the summer 

 generation of females 

 determines whether the 

 larvae will be well upward 

 in the straw, and there- 

 fore removed after har- 

 vest, or lower down and 

 consequently left in the 

 field in the stubble. 



"The method of ovi- 

 position and the point 

 where the egg is usually 

 formed is shown in Fig. 

 103. The larva forms no 

 gall, nor does it harden 

 the stem within which it 

 develops. There is nor- 

 mally but one larva in each joint; but if several eggs have been 

 placed between joints and produce larvae there will be one in the 

 centre of the stem just above the joint and others in the walls just 



FIG. 107. Wheat straw-worm, showing 

 point where female of the spring form 

 deposits the egg in young wheat in early 

 spring. Enlarged showing position of egg 

 at right. (After Webster, U. S. Dept. Agr.) 



