August 22, 1919] 



SCIENCE 



189 



From Part VI., " Insect Luminosity," the fol- 

 lowing extract is taken: 



Of all the manifestation of luminescence among 

 animals there is none more curious, or, in the pres- 

 ent state of our knowledge, more inexplicable, than 

 the manner in which large numbers of individuals 

 of certain fireflies are able to display their light 

 with absolute apparent simultaneity and unison 

 and with regular intervals of darkness, under cir- 

 cumstances which make it impossible for all the 

 members of the swarm to see one another. Even 

 the power, possessed by some peculiar South-Amer- 

 ican beetles, of showing lights of different colors 

 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 soU 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 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 individ- 

 uals, 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 points had been, and would 

 be again immediately. A similar power of display- 

 ing 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 Pro- 

 fessor Poulton has pointed out to me, the rhythmi- 

 cal 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. 



It will be noted first that Annandale's ac- 

 coimt is very circumstantial, perhaps more 

 detailed than any account yet at hand. Sec- 

 ondly it should be noted that he writes that 

 " it is said to be often manifested both in 

 Siam proper and among the mangrove swamps 

 of Perak and Selangor in the west." In other 

 words this phenomenon is not so unusual in 

 Malaya as might be sxirmised from its rare oc- 

 currence in our country. 



Antedating Annandale by twenty years is 

 an account by Burbidge of an excursion on 

 the Scudai Eiver, Jahore (Johore?), near 

 Singapore. He says (1880) that: 



The silence of the night was unbroken, save by 

 the regular dip of the oars, and as darkness in- 

 creased, the tiny lamps of the fireflies became vis- 

 ible here and there among the vegetation on the 

 banks. As we glided onward, their numbers in- 

 creased, until we came upon them by thousands, 

 evidently attracted by some particular kind of low 

 tree, around which they flashed simultaneously, 

 their scintillating brilliancy being far beyond what 

 I could have imagined to be possible.i 



Still earlier than Burbidge we may find in 

 Sir John Bowring's " The Kingdom and Peo- 

 ple of Siam: with a Narrative of the Mission 

 to that Country in 1855 " : 



How can I pass the fireflies in silence? They 

 glance like shooting stars, but brighter and love- 

 lier, through the air, as soon as the sun is set. 

 Their light is intense, and beautiful in color as it 

 is glittering in splendor — now shining, anon extin- 

 guished. They have their favorite trees round 

 which they sport in countless multitudes, and pro- 

 duce a magnificent and living illumination; their 

 light blazes and is extinguished by a common 

 sympathy. At one moment every leaf and branch 

 appears decorated with diamond-like fire; and soon 

 there is darkness, to be again succeeded by flashes 

 from innumerable lamps which whirl about in 

 rapid agitation. If stars be the poetry of heaven, 

 earth has nothing more poetic than the tropical 

 firefly.2 



1 Burbidge, F. W., "The Gardens of the Sun: 

 or a Naturalist's Sojourn on the Mountains and 

 in the Forests and Swamps of Borneo and the Sulu 

 Archipelago," London, 1880, p. 34. 



2 Bowring went to Siam as minister plenipoten- 

 tiary to negotiate a treaty of peace and open up a 



