﻿OF THE STATE ENTOMOLOGIST. 



53 



Atimy AVoem Tachina-fly. 



^lumber of two- winged flies which are often so numerous that their 

 buzzing reminds one of that of a swarm of bees. The Red-tailed 

 Tachina fly {Exorista leucanice, Kirk, Fig. 32) and the Yellow-tailed 

 Tachina fly (B. Uavicauda Riley, Fig. 33) are known to infest it. 

 ■Seizing the first opportunity to attach their eggs behind the heads of 

 the army-worms, these flies are as persistent in their work of destruc- 

 tion as the worms are restless under attack. No worm carries these 

 eggs into the ground with it but falls a victim to the maggots hatch- 

 ing therefrom, and which in a very short time become flies like the 

 parent. 



Fully eighty per 

 cent, of the worms 

 which I noticed last 

 year had been at- 

 tacked by these 

 Tachina flies, which 

 though rendering 

 most efficient service 

 to the farmer, are not unfrequently supposed yellow-tailkd tachina-fly. 

 by him to be the parent and the cause of the worms.* 



The next most common parasite of the Army-worm is the Mili- 

 tary WiCvo^'A^i^x {Microg aster militavis Walsh, Fig. 34), a little black 

 [Fig. 34.1 clear-wing fly with rufous legs. The larvae of this fly infest 

 the worm in great numbers, and so enfeeble it that it can- 

 not enter the ground, but lingers — sluggish and paralyzed 

 — on some grass or grain stalk. Presently the little para, 

 sites all issue from its body and spin in concert a large 

 Military Mi- amount of cottouj'^ silk, in which each individual forms a 

 neat little egg-like cocoon. These are often mistaken by 

 those unread in Nature's mysteries for Army Worm eggs. No greater 

 •mistake could be made. This little friend is in its turn preyed upon 

 by a secondary parasite ( Glyphe veridascens Walsh) belonging to 

 the Chalcid Family. 



[Fig. O.J.] rji|^^ Glassy Mesochorus {Mesochorus vitreus Walsh), 



is another clear-winged fly that attacks the Army Worm. 

 It is but slightly larger than the preceding, and easily dis- 

 tinguished from it by the more graceful form and by a 

 ^y^ I \ translucent yellowish-white spot in the middle of the ab- 



Glassy Meso- flnmAn 



CHORUS. U""1«U. 



* No less tlian four of my correspondents have expressed belief that, in the language of one ot 

 <hem, the worms came from ' ' a dark colored, fuzzy fly about the size of a blow-fly, which is noticed 

 .around old stack yards just before the worm comes ; and when plentiful, the Army Worm is sure to 

 ifollow." 



