180 THE CANADIAN ENTOMOLOGIST. 



analysis of the elements concerned in producing such brilliance at low 

 temperatures.* 



2nd. Biological observation of the particular arrangement of cells, 

 which enables such an amount of light of a high grade to be produced by 

 the metamorphosis of ordinary tissues, without the heat of incandescence, t 



3rd. Chemical analysis to determine the nature of the proximate 

 principles which are thus oxidized in the production of light without heat.£ 



None of these researches can be conveniently made in the Northern 

 States, but in the Middle and Southern States, and especially in tropical 

 America, they can be readily entered into, and none of them fall properly 

 within the sphere of investigation of Entomologists. 



It is unnecessary for me to expand on the scientific value of the 

 investigations here proposed. Luminosity of a much lower grade than 

 that exhibited by these insects has been generally ascribed by physicists to 

 matter at very high temperatures, even in the cases of Auroras and 

 Nebulae ; and in fact the experiments of Mr. Crookes upon radiant matter 

 under the influence of electrical currents would tend to confirm such a 

 supposition. 



Should, however, the investigations I have suggested justify the belief, 

 as seems probable, that large evolution of highly refrangible light may 

 take place without high temperature, our cosmical theories may need to 

 be partially modified. And should the chemist ascertain with accuracy 

 what precise combination of molecules of the ordinary constituents of 



* Some slight efforts have been made in this line of investigation, but nothing 

 satisfactory has been published. Mr. Meldola (Proc. Ent. Soc. London, 1880, p. iii), 

 observes : " that the exact nature of the phosphorescence was still an unsolved problem 

 both to the physicist and biologist. Some years ago he had examined the spectrum of 

 the glow-worm, and found that it was continuous, being rich in blue and green rays, and 

 comparatively poor in red and yellow." 



+ In regard to the structure of the light-giving organs, I have found only some 

 superficial notices by authors whom it is scarcely necessary to cite on the present occa- 

 sion. It is narrated that they are rich in fat cells, and abundantly supplied with nerves 

 and air-tubes ; the histological observations of Schultze do not show the manner in 

 which the light is produced. 



t As to the composition of the fats contained in these special organs, I believe that 

 no investigation has been made, though in this instance, as in the cases of the acid 

 secretion of Harpahcs, the liquid explosively emitted by Brachimis, and the singular 

 excretion of Chlaenius, which combines the odor of camphor and kreasote, the materials 

 are easily procured, and the results would be physiologically important. 



