COLEOPTERA — BEETLES. 239 



machinery to be allowed to fall into disuse. The 

 fact is, that the light emitted by the male is at a 

 certain period nearly as bright as that of the female, 

 but is only visible when the wings and wing-cases 

 are expanded in flight ; and the light is also present 

 when the insect is in the larva state, in which stage 

 of its existence it is of no sex. 



It is, however, pretty certain that the light is 

 most brightly shown at the pairing time, when both 

 sexes have arrived at maturity, and thus the old 

 fable, after all, is partly true; which is further proved 

 by the singular formation of the head of the male, 

 which is margined with a horny band, that prevents 

 either upward or lateral vision, confining his sight 

 entirely to objects below him in his flight, such, for 

 instance, as the wingless female with her " lover's 

 lamp," who, deprived of the means of flight, is never 

 able to rise from the bank which has been her abode 

 ever since she escaped from the shell of the minute 

 egg deposited there by the parent. 



Glow-worms arc about twenty-one months in 

 their progressive larva stages; that is to say, the 

 larvae hatched about August or September have not 

 attained their full growth till the end of the follow- 

 ing season, when they pass into the pupa state ; and 

 the second year, early in June, the perfect insects, 



