322 



MISSOURI AGRICULTURAL REPORT. 



migrate in a mass and march in search of fresh fields. This has given 

 the name of army-worm to this particular insect also, and since this 

 migration in great armies occurs in the fall of the year, it has been 

 called the fall army-worm. The insect is, to be sure, closely related to the 

 true army-worm, but can be readily distinguished from it. 



The moths differ from one another greatly, but are, as a rule, of a 

 light gray color, with the hind wings more or less whitish and semi- 

 transparent. The insect is a little smaller across its expanded wings than 

 the true army-worm, as a rule, not greatly exceeding one inch. In col- 

 lecting a good many of the moths, one will notice that they vary from 

 the color just described to those individuals that have a considerable 

 admixture of bluish white. The markings on the fore wings are quite 

 different from those of the true army-worm. A good idea of the general 

 appearance, size and variation of the fall army-worm may be had by look- 

 ing at figure 63. 



The larvae or worms are also quite different and readily distinguished 

 from the true army-worm. They are not quite as large when they are full 

 grown. The bands along the sides are broader, and the insect is spotted 

 with small dark or black tubercles, on the end of each of which a short 

 black hair is found. The head has a V-shaped mark upon it, which is 

 not found on the true army-worm. The worms, when full grown, are 

 a little over an inch in length, with a brown head, the body striped with 

 greenish-gray above, and a broad dark stripe along the sides, below which 

 is a band of dull yellow. Underneath, the insect is greenish-gray, and 

 on tlie back are three lines of yellow. A good illustration showing tiie 

 general size and characters of this larva will be found in figure 62. 



The eggs are deposited by the parent moth more frequently on the 



under side of leaves, on small twigs of trees and 

 on bushes in the neighborhood of low meadows, 

 as well as on the rank growing vegetation. 

 There are also three broods of this insect each 

 year in Missouri, but unlike the true army- 

 worm, the larvae of this insect rarely occur in 

 great numbers until the third or fall brood, by 

 which time the insects may become so extremely 

 numerous within certain areas as to destroy 

 the plants upon which they are feeding, and 

 therefore be forced to migrate in a mass. 

 wSm,^^-i;St,yT,m ^fluji'- These insects, if they attract the attention 



pirtla: a, larva, natural r .t • i- • i. n j • .1 i i. 



size; b, its head, enlarged; "^ the agriculturist, usually do SO m the late 



V, d, its body segments' 1 r n 1 ^ . 1 • 1 ^1 1 f 



enlarged. (Kiom Riley.) corn and fall wlieat, to which they march from 



