274 NATURE-STUDY REVIEW [15:7— Oct., 1919 



Its silk is strong and smooth, very lustrous, and extremely durable. 

 Each cocoon gives about eight hundred feet of unbroken silk. 



Food plants. — Oak, elm, maple, chestnut, walnut, beech, 

 birch, apple, pear, wild cherry and many others. 



The eggs. — These are flat and round like a lozenge; the top 

 and bottom are white and the sides brownish. They are laid 

 in clusters, usually on the under side of the leaf. They hatch 

 from ten to fifteen days after being laid. 



Polyphemus moth 



The caterpillar. — When first hatched the caterpillar has a large 

 reddish head and the body is yellotw. Later the body turns green, 

 the back being bluish in tint ; the tubercles are yellow. It changes 

 its skin at intervals, as do the other silk-worms, but the color 

 of the body does not change noticeably. When the caterpillar 

 has reached its full growth, its body is green with oblique yellow 

 strips on each of the abdominal segment^. The tubercles are 

 orange, sometimes red. The shield on the rear end of the body 

 is edged with brown and the head is reddish-brown. The seg- 

 ments of the body are deep and sharp at the edge. The cater- 

 pillar has a way when resting, of drawing itself up so that its 

 segments look like a half shut accordian. It will erect the front 

 part of the body if disturbed and hold istelf thus motionless for 



