INSECT ENEMIES OF EASTERN FORESTS 391 
gray or brown and marked with darker wavy or zigzag lines. The 
hind wings in most species are more or less black and conspicuously 
and broadly banded with shades of red, yellow, or white, which sug- 
gested the common name “underwings.” When at rest the hind wings 
are entirely covered by the forewings. Barnes and McDunnough 
(23) published a paper on the life histories of these moths. The full- 
grown larvae range from about 11% to 8 inches in length, and in color 
from lght to dark shades of gray and brown, mottled, dotted, or 
streaked with darker shades. They may or may not have lateral fila- 
ments and a dorsal wart on the fifth abdominal segment. When they 
are at rest during the day, the colors of both larvae and the moths 
blend with those of the tree trunk or other objects which they select 
as resting places. The larvae of most species feed on the foliage of 
forest and shade trees or shrubs, but are not considered as serious 
defoliators. Present knowledge of this genus indicates that all species 
have one generation a year and pass the winter in the egg stage. 
The genus Acronicta has nearly 100 species, many of which are in- 
digenous to the eastern part of the United States. The larvae of most 
species feed on the foliage of forest and shade trees and, although 
some are very common, they seldom if ever become abundant enough 
to cause serious defoliation. In general, the adults are remarkably 
similar to one another, most species being moderately robust, gray 
and white with black markings, head somewhat retracted, thorax and 
abdomen untufted, legs unarmed, and antennae simple in both sexes. 
Many species have a daggerlike mark near the anal angle of the fore- 
wing, hence the common name “dagger moths.” The larvae, however, 
exhibit a wide diversity in their external characters. Smith and Dyar 
(384) classified many of the species into five groups and gave adult 
and larval descriptions. Although some species have two generations 
a year, the majority probably have only one, and apparently in all 
cases the winter is passed in the pupal stage. A few of the more 
common species are discussed in the following paragraphs. 
The cottonwood dagger moth (Acronicta lepusculina Guen.) has 
been the center of considerable confusion because of the diversity 
among the adults in this species and as a consequence many names 
have been added to the synonymy. The full-grown larva (fig. 78) 
is about 114 inches long, rather densely clothed with long, soft, yel- 
lowish hairs, and on the backs of abdominal segments 1, 3, 4, 5, and 8 
are single, long, black, hair pencils. The head, cervical shield, and 
thoracic feet are jet black, the skin of the body is dull whitish, and 
the venter has a brownish tint. The spiracles are black rimmed. 
In earlier instars the body has a greenish tint, the hairs are long and 
white, and the pencils black. This species is distributed through 
southern Canada and the northern part of the United States from 
the Atlantic to the Facific. Poplar is the food plant, though occa- 
sionally it is found on willow. The moths emerge late in May to 
early in July, larvae are found from July to October, and the winter 
is passed in the pupal stage in cocoons composed of silk and bits of 
wood. 
Acronicta leporina vulpina (Grote) is the American form of /epo- 
rina. The full-grown larva is about 114 inches long, and is densely 
clothed in long, fine, curved, white or yellow hairs, with a few bristly, 
black ones on the ends of the body. The head is greenish white, some- 
