LUMINOSITY OF INSECTS. 331 



400. There are a few other Insects not included in these 

 families, which are reputed to possess luminous powers ; and 

 of these the most remarkable are the Fulgorce, or Lantern- 

 flies (fig. 175); of which one species inhabits Guiana, whilst 

 another is a native of 



China. These are in- 

 sects of very remark- 

 able form, having an 

 extraordinary proj ection 

 upon the head ; and 

 this is the part said to 

 be luminous. The au- 

 thority for the assertion, 



however, is doubtful; Fig " 175 - F 



and many Entomologists who have captured the insect, have 

 denied the phosphorescent power imputed to it. But it is not 

 impossible that the female only may possess it, and that it may 

 only be manifested at one part of the year. One of the common 

 English species of Centipede, which is found in dark, damp 

 places, beneath stones, &c., is slightly luminous ; and the 

 common Earthworm is also said to be so at the breeding 

 season. 



401. Of the particular objects of this provision in the 

 Animal economy, little is known, and much has been con- 

 jectured. It is not requisite to suppose that its purposes are 

 always the same ; the circumstances of the diiferent tribes 

 which possess it being so different. The usual idea of its use 

 in Insects, that it enables the sexes of the nocturnal species 

 to seek each other for the perpetuation of the race, is pro- 

 bably the correct one. The light is more brilliant at the 

 season of the exercise of the reproductive functions, than at 

 any other ; and is then exhibited by animals which do not 

 manifest it at any other period. Moreover, it is well known 

 that the male Glow-worm, which ranges the air, whilst the 

 female, being destitute of wings, is confined to the earth, is 

 attracted by any luminous object; as are also the Fire-flies, 

 which may be most easily captured by carrying a torch or 

 lantern into the open air : so that the poetical language 

 in which this phosphorescence is described as " the lamp of 

 love the pharos the telegraph of the night, which marks 

 by its scintillations, in the silence of the night, the spot 



