﻿OS" THE STATE ENTOMOLOGIST. 179 



large white maggot. The worm subsisted upon the grasshopper, 

 finally causing its death, when it cut its way out and entered the earth. 

 In this way probably half were destroyed, often covering the ground, 

 and filling the furrows in plowed fields with their carcasses. The 

 remainder took to flight, moving southeast, when their wings were 

 sufiiciently developed, and we lost trace of them on the great Plains." 

 Mr. J. W. Crow, of Bigelow, Mo., in his correspondence with me, 

 describes these maggots as infesting the "hoppers" in Holt county 

 last Fall ; and in 1869 I received the parasite from John P. Dopf, of 

 Kock Port, Atchison county, and have bred it from the Differential 

 Locust, figured further on, and from the Carolina Locust ( (Edipoda 

 ■i^arolina^ L.) in St. Louis county. 



Finally, Mr. S. E. Wilber, of Greely, Col., has published an account 

 -of what is evidently the same fly.* In this account, after showing 

 how persistently the fly pursues the Locust — leaving it no rest, and so 

 effectually weakening whole swarms as to render them harmless — he 

 expresses the opinion that the constant importunities and annoyances 

 of this fly are the cause of locust migrations. While, however, they 

 jnay constitute a factor in the result, such a conclusion is too sweeping. 

 The Iled-tailed Tachina-fly (Fig. 38) which is so useful in destroy- 

 ing the Army-worm, will serve to illustrate 

 the species, and, indeed, differs scarcely at all 

 except in having the tip of the abdomen red. 

 These Tachina-flies firmly fasten their eggs 

 — which are oval, white and opaque and quite 

 tough — to those parts of the body not easily 

 reached by the jaws and legs of their victim, 

 rkd-tailed rAcniNA-iiA. ^^^ i\\wQ prevent the egg from being detached. 

 The slow-flying locusts are attacked while flying, and it is quite amu- 

 sing to watch the frantic efforts which one of them, haunted by a 

 Tachina-fly, will make to evade its enemy. The fly buzzes around, 

 waiting her opportunity, and when the locust jumps or flies, darts at 

 it and attempts to attach her egg under the wing or on the neck. The 

 attempt frequently fails, but she perseveres until she usually accom- 

 plishes her object. With those locusts which fly readily, she has even 

 greater difiiculty; but though the locust tacks suddenly in all direc- 

 tions in its efl'orts to avoid her, she circles close around it and gen- 

 erally succeeds in accomplishing her purpose, either while the locust 

 is yet on the wing, or, more often, just as it alights from a flight or a 



♦Popular Science Monthly, IT, j). 745. 



