204 



LEPIDOPTERA. 



and elm. These eggs hatch about the same time as 

 those of the spring canker-worm moth.^ The larva 

 (Fig. 155,/; ^, an enlarged ring of larva, side view; 

 d, dorsal view showing markings) has six thoracic 

 legs, but only three pairs of abdominal prop-legs ; and 

 the spring canker-worm (Fig. 157, a) has only two 

 pairs of prop-legs. The larvae (Fig. 155,/) are called 



Fig- 155- 



"loopers," "measuring-worms," and ''geometricians," 

 as they loop the body when walking. This is done 

 by taking firm hold of an ob- 

 ject with the prop-legs, then 

 extending the body and grasp- 

 ing another object with the 

 thoracic legs, after which the 

 body is drawn upward and for- 

 ward in the form of a loop. 

 The larva also extends its body 

 as seen in the drawing and 

 In so doing, it 

 resembles a twig, and as these larvae are eaten by 



holds It in this position a long time 



^ See Third Rep. U. S. Ent. Com., Chap. VII. 



