142 FLASHLIGHTS ON NATURE 



earlier stage, and is hatched out in the form of 

 a crawling worm a type which must have be- 

 longed to a much more original ancestor. It 

 passes the first stage of its life in this worm-like 

 form, but it does not grow by slow degrees, like 

 the earwig, into its final shape. On the contrary, 

 it suddenly boxes itself up one day in a pupa-case, 



NO. 17. THE MOTHER EARWIG SITTING ON HER EGGS. 



or chrysalis, lies by dormant for a while, rearranges 

 its parts entirely, and then rapidly develops into a 

 wholly different creature a bee or wasp, or moth 

 or beetle. The earwig's change is growth ; the 

 butterfly's is a transformation scene. 



How are we to explain these facts ? I think in 

 this way. Long, long ago, the common progenitor 

 of all the insect tribes was a worm-like creature, 



