434 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
The moth of the elm spanworm (Lnnomos subsignarius (Hbn.)), 
also called the snow-white linden moth, is frail and pure white, and 
has a wing expanse of 114 to 114 inches. The forewings are an- 
gulated, and the hind wings more or less notched. The full-grown 
larva is about 114 inches long, with the large head and the anal seg- 
ment bright red and the body dark brown to blackish. ‘This larva 
closely resembles an elm twig (fig. 91, 7.). 
This moth is recorded from Nova Scotia, Canada, the Atlantic and 
Middle States, and Colorado. The food plants include elm, basswood, 
red maple, yellow birch, and other deciduous growths found in low- 
lands. Sometimes it is a serious pest of shade and forest trees, occa- 
sionally defoliating large areas in forests, particularly in maple 
swamps. The moths emerge in July and lay their eggs in clusters on 
tree trunks and beneath branches. The winter is passed in the egg 
stage, and hatching takes place in the spring at about the time the 
foliage opens. The larvae become full grown in June and transform 
to pupae between leaves spun together, on the undersides of branches 
or in crevices of the bark. 
The full-grown larva of Vepytia canosaria (Wlkr.) is about 1 inch 
long. The head is pale whitish, or sometimes reddish brown, with 
five or six large and some minute black dots. The body is whitish 
with a yellowish or reddish tinge marked with black dots and a yellow- 
ish lateral stripe, below which are four dark, wavy hair lines. Some 
specimens have a subdorsal row of white spots edged with brown. 
This species occurs through eastern and southern Canada and in the 
northeastern part of the United States. The larvae feed on hemlock, 
spruce, fir, and larch. The moths emerge in August and September, 
and the larvae are active from June to August. 
The genus Lambdina (Ellopia auct.) was erected by Capps (80), 
because in the study of this group he found that no species of true 
Lambdina occurs in the New World. This genus includes some 
of the most serious defoliators of coniferous forest trees in North 
America. In recent years at least five species are known to have 
occurred in outbreaks, either locally or over extensive areas, and in 
different parts of the United States and Canada. The larvae of 
some of these species are very similar in color and markings. “The 
larvae of pellucidaria, athasaria (Wlkr.) and fiscellaria Guen. are 
alike at maturity, within the normal range of variation, so that they 
cannot be distinguished with certainty” (Dyar, 747). The three are 
important in the Eastern States and are discussed in detail below. 
The moth of the hemlock-looper (Lambdina fiscellaria fiscellaria 
(Guen.)) varies in color from a creamy tan to a grayish brown with 
a purplish tinge. The wing expanse is about 11/4, inches. The fore- 
wing has two transverse irregular purplsh-brown lines and a dot of 
the same color midway between the lines near the costal margin, and 
sometimes the outer line is bordered externally with ochreous. The 
hind wing has only one transverse line. The full-grown larva is about 
114 inches in length and ranges from yellowish green to grayish or 
darker, and the head and body are flecked with black spots (fig. 91, #). 
This species is distributed from Georgia to Wisconsin and south- 
western Ontario and northeasterly to Newfoundland. The favored 
food plants are hemlock and balsam fir. Various other plants such 
