252 BOARD OF AGRICULTURE. 



tony floss on the back of the worm, but places them close to- 

 gether in symmetrical order. In addition to these small para- 

 sites, there are a few larger ichneumon-flies that infest the 

 worm. I have reared from it Oj)hion purgatus (Say), — a 

 horny, yellow, slender-bodied insect with a short ovipositor. 

 According to Dr. A. S. Packard, jun., the female attaches 

 her bean-shaped egg by a pedicel to the skin of the worm. 

 The footless grub which hatches therefrom, ac- 

 cording to the same author, does not entirely 

 leave the egg-shell ; but the last joints of the 

 body remain attached thereto, wliile the larva 

 reaches over, and gnaws into the side of the 

 worm. The species spins a tough, brown, silken, 

 oblong-oval cocoon. Ichneumon leucanice (Fitch) was reared 

 from the worm by Dr. Fitch; and two other genuine 

 ichneumons that are parasitic on it are fig- 

 ured in Harris's " Injurious Insects." They are 

 shown of the natural size in the annexed cuts. 

 The following is a summary of the natural 

 history of the army-worm. 



The insect is with us every year. In ordi- 

 nary seasons, when it is not excessively numerous, it is seldom 

 noticed : 1st, because the moths are low, swift fliers, and noc- 

 turnal in habit; 2d, because the worms when young have 

 protective coloring, and when mature hide during the day at 

 the base of meadow-grass. In years of great abundance the 

 worms are generally unnoticed during early life, and attract 

 attention only when, from crowding too much on each other 

 or from having exhausted the food-supply in the field in 

 which they hatched, they are forced from necessity to 

 migrate to fresh pastures in immense bodies. The earliest 

 attain full growth, and commence to travel in armies, and to 

 devastate our fields, and attract attention, about the time that 

 winter wheat is in the milk ; this period being two months 

 later in Maine than in Southern Missouri. They soon after- 

 wards descend into the ground, and thus suddenly disappear, 

 to issue again, two or three weeks later, as moths. In lati- 

 tude thirty-nine degrees the bulk of these moths lay eggs 

 from which are produced a second generation of worms, 

 which become moths again late in Jul}^ or early in August. 

 Farther north there is but one generation annually. The 



