588 STA'l E BOARD OF AGRICULTURE. 



ting off of the heads usually occurs very rapidly, so that in two or three 

 days large fields that apparently had been in fine condition are destitute 

 of heads. Now commences the march that gives the name to the army- 

 worm. As if moved by a common impulse, the hungry worms move off 

 rapidly, usually all going in nearly the same direction. In this march they 

 take almost anything that presents itself; many weeds, almost all grasses, 

 many garden vegetables, corn, flax, etc., devastating the section through 

 which they march much after the fashion of a small army. After a few 

 days they become full-grown, if well fed, and pass into the ground, where 

 they change to light-brown pupae just beneath the surface, the insects 

 remaining in the ground as pupae for a time varying with the season and 

 the brood. After a time, however, the pupae split down the back and from 

 each issues a moth, which after mating proceeds to lay a liberal supply 

 of eggs for the next brood. 



In our State there are probably three broods — one in April or May, one 

 in July, and one in September. The second brood, however, is the only 

 one that is to be feared ordinarily. The first or May brood consists of 

 those that have succeeded in passing the winter successfully, and their 

 progeny. It is usually a small brood, and while it may do considerable 

 damage here and there, it seldom assumes the size and habit of marching 

 characteristic of the army-worm at its worst. The second brood, which 

 ordinarily appears in July in our State, is usually the destructive one, 

 while the third brood rarely becomes troublesome. Although the majority 

 of the insects develop with these large broods, a varying number are to 

 be found in any stage at almost aDy time after the snow is gone until 

 quite late in the fall. While the great majority of the September brood 

 pass the winter as pupae, a number progress still farther and hibernate 

 as adults, while some of their eggs hatch, producing young caterpillars, 

 which pass the winter in a partially grown condition. Thus we may find 

 larvae or caterpillars, pupae, and adults all hibernating at the sametime. 



The egg of the army-worm is very small, rounded and nearly smooth, 

 The caterpillar which comes from it, although the individuals vary 

 greatly, is brown with longitudinal stripes running along the sides. In 

 typical specimens, the under side is yellowish-gray and the back gray, 

 mottled very finely with dark brown. The sides are marked with three 

 stripes running the entire length of the body. The middle one is dark 

 brown, while those above and below are light yellow with mottles of red 

 and with creamy margins. The head is yellow, covered with character- 

 istic dark brown or black mottlings. The legs are sixteen in number; 

 six true legs near the head and ten false legs or pro-legs ranging from, 



Fig. 18a. Army-worm (Leucania unipuncta). Fig. 18b Army worm (Leveania untptmcta) 



the middle of the body to the posterior end. This caterpillar when full- 

 grown (Fig. 18b) measures one and one-half inches in length. The worms 



