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 



FIG. 4. Orgyia leucostigma. a, larva; &, female pupa; c, male pupa; d, e, male moth; /, female 

 moth; g, same ovipositing; h, egg mass; i, male cocoons; A;, 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 5 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. 





