216 



THE AMERICAN ENTOMOLOGIST. 



The accompaying illustration (Fig. 154), though 

 darker than it 

 shonld be, will 

 show wherein it 

 ! differs from the 

 Southern Cotton 

 Army-worm, 

 notwithstand- 

 ing the colors of 

 the two moths 



Coiois— LigUticddish blo^Ml, white indare SO nearly 

 '^"^I'J alike. 



In the fourth volumeof the "Transactions of the 

 Illinois State Agricultural Society" (1860), will 

 be found a very complete account by the Senior 

 Editor, of the Army-worm with four of its para- 

 sites, to which account we refer those of our 

 readers who desire to learn more of this singu- 

 lar insect. 



During our visit to Hannibal we ascertained 

 that the worms originated in a large 100-acre 

 field of very rich blue-grass, belonging to Mr. 

 W. R. Flowerree. This gentleman makes a busi- 

 ness of fattening cattle, and intended feeding off 

 the grass in the fall; but that same field had 

 neither been pastured nor x)lowed the year before, 

 which in our minds was the very reason wliy the 

 worms originated there. The Army-worm, like 

 our cut-worms and almost all the insects of the 

 great group of Owlet-moths {IN'octua family) to 

 which it belongs, is single brooded, and though 

 a few of the pupa; may remain in the ground 

 through the winter and not issue as moths till 

 the following spring, yet the great bulk of them 

 issue, as above stated, in about a fortnight after 

 becoming pupsB, or during the month of July. 

 These moths pair and the female deposits her 

 eggs where nature teaches her that those eggs 

 will have a chance to live and hatch ; namely at 

 the base of perennial grass-stalks, or on the 

 stubble left by the mower. Consequently you 

 effectually destroy the eggs and thus check the 

 further multiplication of this insect, either by 

 burning your meadow stubble in the dead of 

 winter or by plowing it under in the fall. It 

 were useless to enumerate the many facts which 

 distinctly lead us to this conclusion ; suffice it to 

 say that they are numerous, and that the one 

 mentioned above is corroborative. 



Mr. Trabue has large meadows, separated 

 only by a road from the blue-grass field of Mr. 

 Flowerree ; and he thought he could keep out 

 the worms by simply making a V-shaped ditch ; 

 believing that they could not crawl over, so long 

 as the earth crumbled. The first evening after 

 it was dug, this ditch seemed to be effectual, and 

 tlie bottom was covered with one seething. 



twisting mass of the worms ; but a heavy rain 

 came on in the night following, after which they 

 crossed without difficulty. Mr. Jas. Dimmitt 

 however, who had 80 acres of wheat adjoining 

 the fatal blue-grass field, effectually protected it 

 by surrounding it with a ditch which had the 

 inner side slanting under, towards the field it was 

 intended to protect. It was indeed most fortu- 

 nate that Mr. Dimmitt had hit upon the true 

 method in the beginning, for his wheat was yet in 

 that soft state, in which even the ear would have 

 been devoured, and friend Trabue was not long 

 in profiting by his example. "\Ve noticed that 

 though the worms would nibble at clover, they 

 did not relish it, and always passed it by un- 

 touched, whenever blue-grass or timothy were 

 at hand. A large gang of hogs were malyng 

 commendatory efforts to gobble up all those 

 worms that were crossing the road iu a particu- 

 lar place ; but they utterly failed to check the 

 onward march of this living, and to them, 

 luscious food. 



To one who has never before seen this insect 

 iu its might, the sight of the myriads as they 

 return thwarted in their endeavors to cross, or 

 of the living, moving and twisting mass Avhich 

 sometimes fills the ditch to the depth of several 

 inches ; is truly interesting. "We were much 

 surprised to find tliat, wherever we went, fully 

 nine worms out of eveiy ten had upon the tho- 

 racic segments, just behind the head, from one to 

 four minute, narrow, oval white eggs, about 

 0.04 long, attached firmly to the skin; and our 

 companions were as much surprised when we 

 informed them that these were the eggs of a 

 parasite, and that every one of the worms which 

 had such eggs attached to them, would event- 

 ually succomb to one of the maggots these eggs 

 produced. The large two-winged parasitic flies 

 which deposited these eggs, were wonderfully 

 numerous, buzzing around us and about the 

 worms like so many bees, and the moment we 

 caught one, we recognized it as the Red-tailed 

 Tachina Fly {Exorista militaris, Walsh), 

 which in 1861 was first reared and described by 

 the Senior Editor. As this fly is one of the 

 most abundant Army-worm parasites, and con- 



[Fig. 155.] 



sequently one of 

 its most eflectual 

 cheeks, we repre- 

 sent it at Fig. 

 155. There have 

 been men foolish 

 enough, in the 

 past, t o believe 

 that, because this 

 fly issued from the 

 body of the Army- 



Colors— Gray, black and brick-red. worm, therefore it 



