FAMILY NOCTUIDAE 
UNDERWING MOTHS 
This is the largest of all the families of Lepidoptera in North 
America. The adults are mostly nocturnal in habit. The majority 
of the moths attracted to lights at night belong to this group. 
The larvae are usually dull-colored and naked. Many are foliage 
feeders, some are borers, and others gnaw in fruits. Many are 
found on the foliage of forest and shade trees and shrubs, but 
they usually do not cause serious damage. Other species attack 
seedlings in nurseries and young trees in plantations and occa- 
sionally cause serious injury. This family has received extensive 
treatment by Smith and Dyar (658), Crumb (176), and Knutson 
(433). 
The genus Acronicta contains upwards of 100 species, many 
of which feed on the foliage of forest and shade trees. Some are 
known as “‘dagger moths” because of the presence of a dagger- 
like mark near the anal angle of the forewing. | 
The American dagger moth, Acronicta americana (Harr.), oc- 
curs throughout eastern United States and from Newfoundland 
to Alberta, Canada. Its hosts include a wide variety of hardwoods 
such as boxelder, basswood, red and sugar maples, white and 
yellow birch, elm, ash, oak, willow, hickory, and sycamore. Full- 
grown larvae are about 50 mm. long. They are clothed with fine, 
yellowish hairs and there are long, black hair pencils on the 
backs of abdominal segments one, three, and eight. Larvae are 
present from June to October, and winter is spent in the pupal 
stage in dense silken cocoons. During an outbreak in Maine in 
1945, larvae were so abundant that they literally swarmed all 
over buildings and gardens. 
The cottonwood dagger moth, Acronicta lepusculina Guen., oc- 
curs from coast to coast in southern Canada and the Northern 
States. Its favorite hosts appear to be trembling aspen and 
willow, but it also occasionally infests other species of poplar. 
Full-grown larvae are clothed with long, soft, yellowish hairs and 
are about 37 mm. long. There are single, long, black hair pencils 
on the backs of abdominal segments one, three, four, five and 
eight. Larvae are present from July to October. Winter is spent 
in a cocoon composed of silk and bits of wood. 
Many other species of Acronicta are also found on trees in 
eastern forests. Some of these with some of their more common 
tree hosts are as follows: A. innotata Guen.—hickory and birch; 
A. morula Grote & Rob.—elm and basswood; A. interrupta Guen. 
elm, cherry, birch, and apple; A. lithospila Grote—hickory and 
oak; A. funeralis Grote & Rob.—hickory, elm, and birch; A. 
modica Wlk.—oak; A. retardata (Wlk.)—maple; A. leporina vul- 
pina (Grote)—poplar, willow, and birch; A. distans (Grote) — 
birch, cherry, poplar, willow, apple, and alder; and the smeared 
dagger moth, A. oblinita (J. E. Smith)—usually hebaceous vege- 
tation but also occasionally poplar, willow, boxelder, wild cherry, 
alder, and apple. 
The genus Catocala contains many large, conspicuous species, 
the larvae of which feed on the foliage of various forest trees 
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