260 THE GLOW-WORM. 



dows, and the bottoms of hedges. The utility of the 

 bright light of the females is supposed to consist in 

 attracting the attention of the males during the 

 dark, when, alone, they are able to render them- 

 selves conspicuous. They always become much 

 more lucid when they put themselves in motion. 

 This would seem to indicate that their light is ow- 

 ing to their respiration ; in which process,, it is pro- 

 bable, phosphoric acid is produced by the combina- 

 tion of oxygen gas with some part of the blood, and 

 that a light is given out through their transparent 

 bodies by this slow internal combustion. By con- 

 tracting themselves, the insects have a power of en-' 

 tirely withdrawing it : when they are at rest very 

 little light is to be seen. Mr. Templer, who made 

 many observations on these insects, says that he ne- 

 ver saw a Glow-worm exhibit its light at all, with- 

 out some sensible motion either in its body or legs. 

 This gentlemen, when the light was most brilliant, 

 fancied it emitted a sensible heat *. 



If the insect is crushed, and the hands or face are 

 rubbed with it, they contract a luminous appearance 

 similar to that produced from phosphorus. When a 

 Glow-worm is put into a phial, and the phial is im- 

 mersed in water, a very beautiful irradiation will be 

 found to take place. 



* Phil. Tran. vol. 6. 



