114 



THE BROWN-TAIL MOTH 



Fig. 9. — Young Brown -Tail 

 Moth caterpillars, just from 

 nest; 4 times natural size. 



daily press concerning the effect of 

 the warm weather of January 21- 

 23, 1906, upon the caterpillars, 

 some stating that they had emerged 

 from the webs. As far as we have 

 been able to observe none of the 

 caterpillars emerged at that time. 

 The influence of the unusual tem- 

 perature conditions is now being 

 studied by us, by determining the 

 mortality of the caterpillars in the 

 webs at different periods during 

 the winter. Had the warm weather 

 been followed by a very sudden 

 low temperature, the effect upon the caterpillars would 

 more probably have been fatal. Various experiments upon 

 this point were conducted last winter and are being contin- 

 ued, but are not at present conclusive. 



When they first emerge from the winter nest the young 

 caterpillars (Fig. 9) are of a blackish color covered with 

 warm-brown or reddish-brown hairs. The head is jet black, 

 while the body 

 is marked with 

 yellow when 

 seen under a 

 lens. Project- 

 ing from the 

 back of the 

 fourth and fifth 

 segments is a 

 large tuft of 

 reddish-brown 

 hairs, looking 

 like a brush, 



and about two p^^ lo.— second spring stage of the caterpillar, en- 

 thirds the height larged 4i times; natural size shown by line. 



