LUMINOUS INSECTS. 411 



fact of tiieir being the sexes of the same insect, in the 

 course of our inquiries you will find that sexual (diffe- 

 rences even more extraordinary exist in the insect 

 world. 



It has been supposed by raaiiy that the males of the 

 different species of J^ampi/ris do not possess the pro- 

 perty of giving out any light; but it is now ascertained 

 that this supposition is inaccurate, though their light 

 is much less vivid than that of the female. Ray first 

 pointed out this fact with respect to L.-noctiluca^. 

 Geoflfroy also observed that the male of this species has 

 four small luminous points, two on eachof tlie two last 

 segments of the belly'' : and his observation has been 

 recently confirmed by Miiller. This last entomologist, 

 indeed, saw only two shining spots; but from the in- 

 sect's having the power of withdrawing them out of 

 sight so that not the smallest trace of light remains, he 

 thinks it is not improbable that at times two other 

 points still smaller may be exhibited, as Geoffroy 

 has described. In the males of Ij. Splendidula and of 

 L. hemiptera the light is very distinct, and maybe seen 

 in the former while flying ^ — The females have the 

 same faculty of extinguishing or concealing their light 

 • — a very necessary provision to guard them from the 

 attacks of tl^e nightingale and other nocturnal birds : 

 Mr. White even thinks that they regularly put it out 

 between eleven and twelve every night ** : and they have 

 also the power of rendering it for a while more vivid 

 than ordinary. 



Authors who have noticed the luminous parts of the 



' Hist. Ins. SI. " Hist. ahng. i. 168. " Illiger Mag. iv. 195. 



" Nat. Hist. ii. 279. 



