MOTHS AND BUTTERFLIES. 



451 



FIG. 568. Heliophtla unlpuncta, army- 

 worm moth. 



of the twelfth segment. When they are done feeding they descend to the ground, 

 where they spin light cocoons among the dead leaves, or other materials, and transform 

 to pupas. This species feeds on the leaves of grape, thorn, plum, raspberry, poplar, 

 and probably other trees and shrubs. 



The army-worm, Heliophila unip-uucta, has a remarkably wide distribution, occur- 

 ring in this country everywhere, from Maine to 

 Texas, and from the Atlantic to the Rocky Moun- 

 tains. It has also been reported from South Amer- 

 ica, Europe, and Australia. The moth expands 

 nearly two inches, and the fore Avings are yellowish 

 drab, sprinkled with black scales. A small white 

 spot rests on the median vein, at the end of the cell, 

 and the transverse posterior line is represented by a 

 row of black dots across the wing, on the veins. A 

 dark shade extends from the apex obliquely down and in as far as the above-named 

 row of dots. The hind wings are smoky brown, with darker veins. 



The female moth deposits her eggs between the sheath and stem of grass, or in 

 the fold of a leaf near the base, in rows containing from five to twenty or more, cov- 

 ering them with a white, glistening fluid, which fastens them to the leaf, and draws 

 the edges together so that they are nearly or quite concealed. The egg is white, 

 nearly spheroidal, about one-fiftieth of an inch in diameter, and hatches in from eight 



to ten days. The newly hatched army-worm is so 

 small, and so nearly the color of the grass, that it 

 is generally overlooked, even when present in large 

 numbers. It grows rapidly, reaching maturity in 

 from fifteen to thirty days, during which time it 

 makes five moults. It is then about an inch and a 

 half long, pale 'green on the under side, with longi- 

 tudinal stripes of dark gray or blackish, alternat- 

 ing with stripes of greenish or yellow on the upper 

 side. In a short time the caterpillar works its way down into the ground, where it 

 transforms into a dark-brown pupa, about three-fourths of an inch in length. After 

 remaining in this state about twenty days the moths emerge, and fly only by night, 

 concealing themselves during the daytime. 



There are several broods in a year in the southern parts of the United States, but 

 probably only one in the moi-e northern regions. Professor Riley states that this 

 insect hibernates in both the caterpillar and imago states, and probably also in the 

 pupa, particularly at the north. The food plants of this species are the grasses, both 

 wild and cultivated. At times these insects become so abundant in certain localities, 

 that every plant which can possibly serve as food is completely destroyed, after which 

 they move off to other fields, in vast numbers, in regular order; and from this habit 

 they have received their common name. 



The stalk-borer, Gortyna nitela, expands about an inch and a quarter, and the 

 " fore wings are of a mouse-gray color, finely sprinkled with N"aples-yellow, and they 

 have a faint lilac hue, but are distinguished mainly by an arcuate, pale line running 

 across their outer third." The caterpillar is " of a livid hue when young, with light 

 stripes along the body. When full grown, it generally becomes lighter, with the 

 longitudinal lines broader. This caterpillar bores into the stems of potato, tomato, 



FIG. 569. Leiicania unipuncta, larva, 

 army- worm. 



