62 NATURAL HISTORY. [cH. III. 



pearl colour, with black spots which are surrounded 

 by yellow rings. This caterpillar descends into the 

 earth about the middle of July, where it forms an 



egg-shaped cocoon of bits of earth fastened together 

 by silken threads, from which the moth appears in 

 the following April. One of these caterpillars af- 

 forded Reaumur a good opportunity of examining 

 the proceedings of such caterpillars as form their 

 retreats under ground, as well as the mode in which 

 they procure materials for one or two additional in- 

 ner linings of the cocoon, in the inside of which 



