1900.] INSECTS OF THE " SKEAT EXPEDITION." 865 



possessed by some peculiar South-American beetles l , of showing 

 lights of different colours on different parts of the body at the 

 same time is not more wonderful, or more conspicuous, than this. 

 The phenomenon is not common on the east coast of the Malay 

 Peninsula, where the soil is sandy; but it is said to be often 

 manifested both in Siam proper and among the mangrove-swamps 

 of Perak and Selangor in the west. I have only been able to see 

 it on one occasion, and that was on the bank of the river near 

 Kuala Patani, one fine evening at the end of June. 



A large tree was covered with many hundreds of fire-flies, the 

 majority of which seemed, judging from the similarity of their 

 lights, to belong to one species, or perhaps to one sex. There 

 were three individuals seated together, however, whose lights 

 were larger and bluer than those of the others. The lights of all 

 the specimens of the more abundant variety flickered in unison 

 with one another ; those of the minority, the three individuals, 

 flickered together also, but in a different time. At one instant 

 the tree was all lighted up as if by hundreds of little electric 

 lamps ; at the next it was in complete darkness, except for three 

 blue points. Then, again, it was covered with white points, except 

 for a little patch of darkness where the three blue lights had been, 

 and would be again immediately. A similar power of displaying 

 luminosity in unison is said to be exhibited by some marine 

 animals, even after they have been removed from the water ; but 

 the questions as to how this unison is effected and what is its 

 exact object are obscure. The power by which it is regulated may 

 be somewhat analogous to that which causes all the individuals 

 composing a flock of birds to wheel at the same instant. As 

 Professor Poulton has pointed out to me, the rhythmical display 

 of light among a crowd of individuals appears much more 

 conspicuous to the eye than the simple flickering of a number of 

 independent points. 



Malay Names. — The ordinary Malay term for a fire-fly is Jclip- 

 Tclip, a name which seems to suggest the rapid flickering of the 

 insect's light, though the word klip is used in the sense of to 

 glitter. Our west-coast servants called the luminous beetle larvae 

 with which we met in Patalung, " Jclip-Jclip tanah," land or earth 

 fire-flies. The aquatic species, which they had never seen or heard 

 of before, they christened " klip-klip ayer" or water fire-fly. His 

 Excellency Phya Sukum, the Siamese Chief Commissioner for the 

 Ligor Circle, to whose hospitality and administration we owed 

 much, tells me that he has seen, in the south of Ligor and near 

 Singora, a large green worm which sits on trees, and it is so 

 brilliantly luminous at night that it well deserves its Siamese 

 name of Lightning Grub. On one occasion he secured a specimen, 

 and was conveying it to Bangkok ; but unfortunately it was killed 

 on the voyage through the carelessness of a servant who closed 

 the box in which it was. 



1 See Haase, Deutsche ent. Zeitschr. 1888, pp. 146-167. 



