270 



FNSECTS INFESTING WHEAT. 



often twenty or thirty. The egg is ahout one fiftieth of an 

 inch in length, and it hatches in less than fifteen daj-s. 

 Fig. 260. — Larva of Hessian Fly, 



Fig. 260. 



enlarged — color, yellowislr-white. 

 Fig. 261. — Tlie slieath removed, 



Fig. 261. 



showing three hibernating larva) or maggots of 

 the Hessian Fly. They are now said to be in 

 the fax-seed state, from the resemblance they 

 bear to those seeds. 



Harris says: "The maggot (Fig. 260) which 

 proceeds from the egg is of a pale-red color. The 

 maggots crawl down the leaf and work their way 

 between if and the main stalk (Fig. 261), passing downward 

 till tlicy come to a ])oint a little below the surface of the 

 ground, with tlu' head towards the root of the }>lant. Having 

 thus fixed themselves upon the stalk they ])ecome stationary, 

 and never move iTom the ]>lace till their transformations are 

 completed. They do not eat the stalk, neither ilo they pene- 

 trate within it, as some persons have supposed ; but they lie 

 lengthwise upon its surface, covered by the lower part of the 

 leaves, and are nouvisluMl wholly by the sap. which they appear 

 to take by suction. As they increase in size they grow plump 

 and firm ; they l)ecome embedded in the side of the stem by 

 pressure of their body upon the growing plant. (Fig. 2()2.) 

 The nuiggot thus seldom destroys the 

 })lant ; but where two or three are fixed 

 in this manner around tlu> stem they 

 weaken and impoverish the i)lant and 

 cause it to lall down or to wither and 

 <lie." (Fig. 26;'., right.) 



Fig. 2(>2. — Lower part of an infested 

 wheat plant, showing the swelling at the 

 lower end of the sheath causeil by the 

 larva' of the Hessian fly. 



The maggot reaches maturity in about 

 forty days, and measures about three twentieths of an inch in 

 lensth. 



Fig. 262. 



