11 



DEALING WITH THE DESTRUCTIVE SPECIES OUTSIDE OF THE 



GRAIN FIELDS. 



In attempting to control the grain-infesting Isosoma, the practical 

 farmer will, in several ways, find himself at a disadvantage. The 

 very deceptive resemblance of these insects to ants, and also to others 

 actualh^ beneficial, will prevent his readily recognizing them in the 

 fields, even if he were to see them at all, and it is only when, b}^ acci- 

 dent, perhaps, that he finds the worms in the stems of his grain, that 

 he will ordinaril}' be able to detect their presence. As the develop- 

 ment of the insect takes place entirely within the straw, rarely, 

 except in the case of two species, showing any external effects, much 

 injury may occur to the kernels of grain without his being able to 

 determine the cause. It is, therefore, advantageous to him to know 

 that he may reduce the chances of injury by careful attention to the 

 uncultivated areas that inevitably surround his cultivated fields. As 

 an illustration of the influence of neglecting uncultivated patches like 

 fence corners and roadsides, and allowing these to become overgrown 

 with the different species of rye grass (Elymus), I give the results of 

 my own rearings of these insects from stems of grasses, taken from two 

 different localities along the Illinois Central Railway. In connection 

 with what is here given, it might be well to call attention to the fact 

 that the grounds within the fences along our more important railwa3^s 

 are usuallv better kept than are similar uncultivated grounds along 

 the highways, to sa}' nothing of the fence corners, borders of open 

 ditches, and similar tracts on the premises of the farmers themselves. 



The locality from which I secured the greatest number of barley 

 straw'-worm flies {Lsosoma horde!) is situated about 2 miles north of 

 Champaign, 111. The contour of the ground is such that mowing over 

 in summer is difficult, and burning over in winter, though practical, 

 probabl}" did not seem necessar}" to the railway people. As a conse- 

 quence, a small tract grew up to the Canadian rye grass {Elymus 



