266 



A.V ECONOMIC ENTOMOLOGY. 



to brown or rwlilish, sometimes even to blackish, the hair being 

 oftlie colors indicated, and the surface of the l^ody hardly visible. 

 The commonest of all, perhaps, is the Spilosonia virginica, or 

 "white ermine moth," and this is whitish or yellowish, produc- 

 ing a snow-white moth, the wings a little black dotted, the sides 

 of the abdomen and front legs yellow. Another species often 

 seen crawling about during late fall is Pyrrhardia Isabella, and 



Fig. 287. 



Spi/osonia viio^inica. the white ermine moth. — a, larva; b, pupa; r, adult. 



this caterpillar may be recognized by ha\ing the central portions 

 of the body red-brown, while the anterior and posterior segments 

 are black. This produces a uniformly brownish-yellow moth. 

 All the moths fly at night, and are but rarely seen during the 

 day, and all the caterpillars, where they become troublesome, 

 are within reach of the arsenites. 



An exception to the general feeding habit we find in Hyplian- 

 tria cnnea, the caterpillar of which is known as the "fall web- 

 worm." The moth is white, sometimes without spot or mark 

 of any kind, usually with onlv a few black dots, but occasionally 

 with the spots forming more or less evident bands across the 

 wing. The eggs are laid in masses on trees, and the larvae, as 

 soon as they hatch, form a little web in which they remain so- 

 cially, except when feeding. They eat first the leaves within, 

 then those close to their nest, gradually separating until some- 

 times an entire tree becomes defoliated from a single point. This 



