THE SOLITARY BEES 11 



This stage corresponds to the chrysalis of a 

 moth or butterfly, the creature being shortened 

 up and rather more like the perfect insect com- 

 pacted into the smallest form possible. People 

 are often misled into the idea that the caterpillar 

 forms the chrysalis over its former self, whereas 

 the chrysalis has been all the time forming 

 inside the caterpillar and only shows itself when 

 the final skin is shed ; of course some caterpillars 



FIG. 1 . Bombus, larva and nymph : after Packard. 



spin a cocoon over themselves before they change 

 their skin, but then the true chrysalis is found 

 inside the cocoon. A curious fact connected 

 with the change from the nymph to the perfect 

 insect is that this takes place sometimes as 

 early as August in the year preceding their 

 appearance ; so that cells dug up in August 

 may contain fully fledged insects which are not 

 due to appear till April or May of the following 

 year. It is wonderful also how long life can be 



