BEETLES 173 



On Mt. Matang I found larvae of a species of Luciola 

 living in a trickling stream, or in the moss on its 

 margins. They were phosphorescent, just like our 

 English Glow- Worm, and like it also appeared to feed 

 on snails. This may possibly be the same species as 

 that found by Dr. Annandale in the Malay Peninsula 1 

 in a stagnant pool, which he observed to display their 

 light only when the water was quite still and when 

 they were resting on plants near the surface. When 

 the water was disturbed the lights of the larvae 

 disappeared. 



Dr. Annandale indulges in some philosophical 

 speculations as to the display of phosphorescent lights 

 by insects, and it is certainly difficult to explain the 

 significance of the light in Lampyrid larvae. The old 

 explanation that the female Lampyris displays her light 

 to attract the male fails to account for its display by 

 the larvae and by the males themselves. Dr. Annan- 

 dale suggests that the light of the aquatic larvae serves 

 as a lure to attract surface or aerial prey, but I do 

 not accept this explanation of its significance, as the 

 larvae probably prey on molluscs, for which they 

 search. 2 



The same naturalist has discovered another aquatic 

 Lampyrid larva in tanks at Calcutta,3 among the 

 roots of a floating water-plant, Pistia stratiotes. This 

 is probably the larva of Luciola vespertina, a very 



1 P.Z.S., 1900, p. 862. 



2 I should suggest that this light serves as a defence or 

 warning. A small Lampyris flew into my verandah at Singapore 

 and a young Gecko (H emidactylus) advanced to attack it. Just 

 as it was about to seize the Lampyris the latter flashed its light 

 and the Gecko turned and fled [see Note 14, p. 315], H. N. R. 



3 Journ. and Proc. As. Soc. Bengal (A 7 . Ser.\ II. (1907), p. 106. 



