DESCRIPTION OF THE LIFE STAGES 89 



DESCRIPTION OF THE LIFE STAGES 



Egg- The egg mass of this Forest Caterpillar is in the 

 form of a belt encircling the smaller twigs of the various 

 food-plants. Its general shape is represented in Fig. 21, the 

 length of the belt varying from one-fourth to one-half of 

 an inch ; the diameter is usually one-fourth of an inch. 

 The belt terminates abruptly at each end, although it is not 

 as a rule squared off. The outside of the belt consists of a 

 glistening, varnish-like, brownish or lead-gray material, which 

 covers the eggs. When the eggs are first laid, and for some 

 months afterward, this covering remains entire, but as the 

 winter passes, it becomes more and more broken, so that by 

 spring it generally has a rather ragged appearance. Bv remov- 

 ing the covering, the eggs will be found beneath, resting side 

 by side at right angles to the supporting twig. Each egg is a 

 trifle longer than wide, and is covered with a reticulated net- 

 work of the same varnish-like material that conceals the mass 

 as a whole : this net-work serves to attach the eggs to the twig 

 and to each other. The eggs are of a dull gray color, show- 

 ing white in some places. When the caterpillars hatch they 

 gnaw off a circular cap on the upper end of the egg, and come 

 out through the hole thus made. Each egg is about one-twen- 

 tieth of an inch long. The number of eggs in one belt varies 

 from less than 150 to more than 225, the average being nearly 

 200. 



Larva. The full-grown Forest Tent Caterpillar has a cyl- 

 indrical body about two inches long and a little more than a 

 quarter of an inch thick. It is rather sparsely clothed with 

 brownish hairs. The general color is bluish. Along the middle 

 of the back there is a series of double whitish or cream-colored 

 spots having the appearance of Fig. 22, a. By means of these 

 spots the caterpillar may easily be distinguished from the com- 

 mon American Tent Caterpillar; in the latter species the line 

 along the middle of the back is continuous (Fig. 28, a) . On the 

 upper part of each side of the Forest Caterpillar there runs a 

 rather broad blue line, edged above and below with a narrow, 

 yellowish-brown line. The head is bluish. Near the front 

 end of the body are three pairs of jointed legs, each with a 



