216 
MEMOIKS OF THE XATIOS^AL ACADEMY OF SCIENCES. 
Harris states that the eggs are laid during July “in clusters on the underside of a leaf,, 
generally near the end of a branch.” He then observes: “ AVhen first hatched they eat only the 
substance of the under side of the leaf, leaving the skin of the npperside and all the veins 
untouched, but as they grow larger and stronger they devour whole leaves from the point to the 
stalk, and go from lea f to leaf down the twigs and branches” (Treatise, p. 425). He adds : The fully 
grown caterpillars ‘‘rest close together on the twigs, when not eating, and sometimes entirely cover 
the small twigs and ends of the branches. The early broods come to their growth and leave the 
trees by the middle of August, and the others between this time and the latter part of September. 
All the caterpillars of the same brood descend at one time and disappear in the night. They 
conceal themselves under leaves, or just beneath the surface of the soil, and make their cocoons, 
which resemble those of the Unicorn ]N'otodouta. They remain a long time in their cocoons before 
changing to chrysalids, and are transformed to moths toward the end of Jniie or the beginning of 
July ” (Ti*eatise, pp. 42,>-42C). Tliis habit of feeding exposed and living gregariously up to the time 
of pupation proves the almost entire iimnunity enjoyed by this caterpillar from the attacks of birds. 
"We have also noticed iu Providence the simultaneous and suddeu disappearance of a whole brood 
from an apple tree at the end of September. 
Eegarding the habits of this species in California, Mr. Edwards states that he detected the- 
caterpillars iu the fall of 1S75 “feeding upon willows in the neighborhood of Mount Shasta. Six 
caterpillars taken, all feeding close together, upon a dwarf willow, their brilliant colors giving to 
the plant at a little distance the appearance of a raceme of showy flowers. In a few days they 
began to undergo their change, and by the 27th of August had all transformed. The perfect, 
insects began to appear on the 22d of Heecmber, a second followed on the Dth of January, and the 
third oil the IGth of March. The remaining specimens all died iu the chrysalis state.” Mr. Dyar- 
found the larvm he describes' on the maple in the Yoseinite Yalley in August. 
The moth has been bred by Mr. Elliot from theAvillow, and T have fouud it in difiereiit stages- 
of growth oil the willow at Brunswick, Me., in August and September. It also feeds on the- 
aspen and blackberry iu Maine. I have also found the caterpillar feeding on the huckleberry 
( Yaccinhun). 
I found the eggs Avith the larvm just hatching on the leaves of the willow at BrunsAAdek, Me., 
June 24, The eggs AA'ere in this case somewhat scattered and few in numher, and the larvm did 
not feed gregariously. The larvm continue to hatch till the early part of August iu Maine, as 
August 14 I found the larA^ne in Stage II and also fully grown on the aspen. 
“ This curious and AAxll-known caterpillar Avas receiA'ed in August from Oregon. Mr. E. S.. 
Mattesou, of Aumsville, states that he found it in large numbers on a young apple tree, entirely 
denuding the branches of leaA^es. This mention is made as bearing upon the geographical 
distribution of the species. The gregarious habits of these larA'ie when first hatched admit of an 
easy remedy in hand picking.” (Riley, Rep. U. S. Dept. Agr., 1884.) 
After the second molt some of the larvm are ichueuuioued. September 2 an iclinenmoii larva 
had issued from the A'enti'al side of the caterpillar and spun a white thin cocoon; the nearly dead 
caterpillar Avas fiistened by its back to the cocoon. After a day or two the caterx^illar died and 
turned whitish, the rows of black warts becoming conspicuous. 
Riley has observed the eggs in June; the larvm from June to October; the moths in May and, 
August. 
Food j)l(mt8, — Apple, cherry, plum, rose, thorn, pear, Betida alha^ aauIIow, aspen, blackberry, 
bramble, huckleberry (UacciUM<m). I have found the laiv^re in Maine most commonly on the 
willoAv, and it is probably from this tree that the insect has migrated to onr fruit trees. In* 
California it feeils on the willow (Edwards) and maple (Dyar). 
In Beutenmiiller’s list, besides the fruit trees already mentioned and difierent species of Avillow,. 
he has found it on the flowering dogwood, sweet gum, persimmon, siiowdroi» tree, bayberry, and 
three different species of hickory. Apricot, Avistaria, oak, locust, hickory, persimmon, poplar., 
(Riley.) 
Geographical dutrihution , — This species has a wide range, extending throughout the Appa- 
lachian, AustroriiDariaii, and Camx>estrian subproviuces from Maine and Canada to Missouri and; 
southward to Texas, Georgia, and Florida. 
