418 



THE WHEAT CULTUKIST. 



Ha:bits of the Wheat MroGE. 



This insect remains in the earth in its larva state, at 

 least ten months in the year, and buries itself in the soil 

 from half an inch to two inches in depth. This is true, 

 at least in regard to the larger number of them. Others 

 remain in the chaff of the wheat, and are conveyed to 

 the grain-mow, or the stack. But there is no positive 

 evidence that these ever become sufficiently vitalized to 

 perpetuate their species, although, according to experi- 

 ments made by Dr. Fitch, of 'New York, there is reason 

 to believe that they do. Certain kinds of wheat are 

 less liable to injury from the attacks of these insects 

 than others. See page 47. Dr. Rathvon is of the 

 opinion that the larvae of the wheat midges do not im- 

 bibe the milky fluid of the young wheat grains ; but 

 feed upon the epidermis or outer integument, and that 

 the destruction or injury of this, is what causes the ulti- 

 mate depletion of the grains. 



Mr. Kathvon is also satisfied that the wheat midge 

 has not the power to puncture or penetrate the chaff of 

 the wheat with its ovipositor, for the purpose of deposit- 

 ing its eggs upon the grain ; nor do the larvae reach 

 it through such a puncture. But the grain is reached 

 through the separation, or opening of the valvules 

 that enclose the grain, generally when it is in bloom. 

 The largest number of the eggs of the insect are de- 

 posited on the outside of the chaff, where they are 

 either washed off by the heavy rains, or are bm^nt or 

 dried up by the hot sun. But, in whatever way 

 these insects may injure the growing wheat, the only 

 effectual remedy has already been given, on pages 415 

 and 416. 



