13 
part of September, in a glistening white, frothy-looking mass attached 
to the outside of the cocoon. They are seen at a glance, owing to their 
pure white color, and remain conspicuous upon the trees until spring. 
The caterpillars hatch in Washington in April and May. They are 
represented at different stages of growth in figs. 4, 5, and 6, and in 
view of the care with which these figures have been drawn detailed 
descriptions will -be unnecessary. They cast the skin five times, 
exhibiting a different character after each molt, as indicated in the 
{ 







SRE rie 
\ NS \ 
IEE pee ESE, 
“Sy O.HEIDEMAN S.C. 
oo 
Fie. 4.—Orgyia leucostigma. a, larva; b, female pupa; c, male pupa; d, e, male moth; /, female 
moth; g, same ovipositing; h, egg mass; 7, male cocoons; k, female cocoons, with moths carrying 
eggs—all slightly enlarged (original). 
figures. The newly hatched young feed on the under surface of the 
leaf, eating off the parenchyma and producing a skeletonized appear- 
ance. After the first molt the skeletonizing continues, but a few holes 
are eaten completely through the leaf; after the second molt many 
holes are eaten through between the main ribs, and after the third 
molt the leaf is devoured, except for the midrib and its principal 
branches. After the fourth molt the caterpillars begin to eat from 
the edge of the leaf and devour everything except the principal veins. 
