THE GLOW-WORM 367 



the mystery. All we know is, that it comes from a thick fluid 

 which lies just beneath the skin, and that it shines through a 

 kind of little window upon the lower surface of the body. But 

 what the fluid is, or why it shines, no one can say. 



Some people have thought that the light enables the beetle to 

 find its mate; but then thousands upon thousands of other beetles 



Glow-worms — Male and Female 



find their mates without any help of the kind. Others have 

 supposed that it serves as a means of protection from birds and 

 other insect-eating creatures; but it certainly attracts toads, for 

 the writer once caught about sixty glow-worms and put them in a 

 fernery, and the toads ate them all in a couple of nights. The true 

 explanation of the light itself, and the means by which the insect 

 controls it, has therefore yet to be discovered. Indeed, the glow- 

 worm is a living puzzle, and not even the wisest and most learned 

 of naturalists is able to tell us very much about it 



