GRASSHOPPERS IN GENERAL. 



31 



be protected, as their food is from insects deleterious to farming in- 

 terests." 



From the description given, it is very probable that the yellow 

 grasshoppers referred to belonged to the species now under consider- 

 ation. 



INVERTEBRATE. The locust finds, however, its most unrelenting 

 enemies within its own class. The accompanying figure 5 shows the 

 immature stage of the locust mite, Trombidium locustarum, Riley. 

 These were found, in 

 some instances, in such 

 numbers on the under 

 side of the wings of the 

 Differential Locust as to 

 cause the wings to stand 

 out from the body. Lo- 

 custs with one wing or 

 both wings eaten off were 

 found. The wings of 

 many were rendered use- 

 less for flight by this 

 mite. According to Ri- 

 ley, this mite drops from 

 the wings when nearly 

 full grown, passes through 

 the pupal state, and comes 

 forth an eight-legged mite 

 to spend the winter, a part 

 of its food being locusts' 

 eggs. In the spring, the 



females deposit from 300 to 400 eggs, which hatch out as young, six- 

 legged mites, that attach themselves to some host, the one chiefly 

 chosen being the locust. This is one of the most effectual enemies 

 of the locust. It is familiar to all. Newspaper reports concerning 

 locusts, this year, nearly always contained some reference to a "little 

 red bug found under the wings." 



Beetles. Predacious beetles and the larvas of beetles are known to 

 prey upon the egg-pods of this species. 



Flies. Last fall, the numbers of this locust seen dead in the fields, 

 destroyed by internal parasites, made me desirous of procuring an es- 

 timate of the interruptions that parasites of this class cause. Accord- 

 ingly, I collected a large number of living forms, retaining and feeding 

 them in closed boxes. I did the same again this year, collecting 130 

 for this purpose. The computations upon these observations have 

 appeared elsewhere, and are herewith given. 



FIG. 5. (Original.) Red mite, Trombidium locustarum, 

 on membrane of wing of locust. 



