FIELD BOOK OF INSECTS. 



colonies on an old cherry tree in his yard because he was 

 going to cut the tree down in the autumn; this winter I 

 must go all over my trees again. 



The common name, Forest Tent-cater- 

 pillar ' f this s P ecies ( Plate LVH ) is 



for it makes no tent although closely related 

 to americana. Its egg-masses resemble those of the 

 other eastern species but are more square-cut at the ends. 

 The larvae eat the leaves of almost any deciduous tree but 

 maple is said to be its favorite. They feed in colonies, 

 when young. Many of the cocoons are placed in curled 

 leaves. 



BOMBYCID.E 



Perhaps the Commercial Silk- worm ought 



om yx not to be in a Field Book since it is not a 



mon 



field-insect. It is probable that, even in its 

 native home, it could not now exist wild since the larval 

 legs have so degenerated that the larvae cannot climb well. 

 The entire family was originally confined to Asia. The larva 

 will eat the leaves of several kinds of plants, such as Osage 

 orange, but it does best on white mulberry. The adults 

 have a wing-expanse of about 1.75 inches, are creamy 

 white and, although the wings seem fairly well developed, 

 the moths do not fly, perhaps because of generations of 

 artificial confinement. Each female lays about three 

 hundred eggs. There are many races which have been 

 produced by man's selection; some have one while others 

 may have as many as six generations a year, also the color 

 of larvae and cocoons differ. If labor were cheap enough 

 in America to make the rearing of silk-worms pay, it is 

 probable that some of our native Saturniidas would be 

 fully as profitable as this species. 



GEOMETRID/E 



Larvae of this family are familiar to almost everyone, but 

 only a small proportion of those larvae which come within 

 our range of vision are really seen, since most of them 

 stiffen themselves and pass for a twig. Others, those 



192 



