100 THE GLOW-WORM 



has arisen through the wingless female, superficially 

 resembling a grub, displaying a far inoro brilliant light 

 than the male, thereby attracting most attention from 

 casual observers. While the male in his ultimate 

 metamorphosis acquires the full panoply of a beetle, 

 with effective wings and horny wing-cases, his spouse 

 retains a larval form through life. Wingless and 

 worm-like, she is doomed to creep humbly in the 

 herbage, trusting that the glow of her lantern may 

 bring her the connubial company to which she feels 

 entitled. Nor does she trust in vain. Winged suitors 

 are astir throughout these brief summer nights, and 

 respond eagerly to the beacon which announces that 

 the lady is at home. 



The material and mechanism of the said beacon long 

 baffled the scrutiny of biologists, nor has the chemistry 

 of animal luminescence been elucidated further than 

 to establish the process of its production as an inter- 

 action of two substances lucifern and luciferase. The 

 resulting light differs in no respect from ordinary light, 

 except that it is all visible, containing no invisible 

 ultra-violet or ultra-red rays. Those who care to know 

 how knowledge of the structure and action of the 

 luminous organs of animals have been acquired, and 

 the degree in which physical and chemical research 

 have elucidated the problem, may study with advan- 

 tage Professor E. N. Harvey's treatise on The Nature 

 of Animal Life. 1 Meanwhile, that indefatigable ob- 

 server, the late J. Henri Fabre, did much to unravel 

 the secret during the last years of his life. 



1 J. B. Lippincott Co., Philadelphia and London, 1920. 



