THE CANADIAN ENTOMOLOGIST. 183 



views due weight, I have cited them at some length in the foot note. My 

 own impression is that Mr. Belt and Sir Sidney Saunders have given, 

 between them, the true explanation of the rhythmic exhibition of light, 

 and that apart from the aesthetic realization in nature of this plan of 

 making night glorious by the wonderful brilliancy of such insignificant 

 objects (upon which idea this is neither the time nor the place to dis- 

 course), it is primarily a defence of the insects against danger, and is 

 secondarily caused by that tendency to act in concert or imitation which 

 operates upon all sentient beings. This tendency may be equally observed 

 in a flock of sheep following its leader, a school room of hysterical girls, 

 a political meeting, a spiritistic se'ance, or a hyper-sentimental religious 

 assemblage. And I regard all these occurrences, however differing in the 

 importance of their final results, as individual instances in a large class 

 of similar phenomena, caused by aggregated sympathy. 



I would therefore agree with Sir Sidney Saunders and Mr. Meldola in 

 quite rejecting Mr. McLachlan's view that it is produced by a change in 

 position of the insects caused by currents of air, or even voluntary move- 

 ments in direction of flight. 



To recur to the process by which the light is produced, I would add 

 to what I have said in the beginning of this essay, that the chemical pro- 

 cesses possible in the bodies of Lampyridae can be scarcely if at all 

 different from those which take place in neighboring and closely allied 

 tribes. We may therefore infer from the observations of Mr. Meldola 

 that the ordinary metamorphoses of tissues, by the aid of some slight 

 modification of composition and cellular structure, are capable of evolving 

 light, which belongs to the upper end of the spectrum, such as is gener- 

 ally significant ot the highest temperatures. 



It is therefore the more extraordinary to find in these insects light of a 

 high order not dependent on elevation of temperature, and consequent 



by sexual influences, amid vast hosts instigated to combine therein, and act in unison. 

 He would rather attribute this phenomenon to an inherent tendency to emit their light 

 from time to time, requiring a certain amount of repose to recruit their powers; and 

 when any thus surcharged felt intuitively inspired to take the initiative, the others — 

 prompted to obey a corresponding influence — followed such suggestion in responsive 

 sequence." Ibid, p. viii. — "Mr. Meldola stated that Mr. Thomas Belt (Naturalist in 

 Nicaragua, p. 320) had expressed his belief that the luminosity of the Lampyridse played 

 the same part as the bright colors of many caterpillars, i. e. , that it served as a danger 

 signal, warning nocturnal foes of the inedibility of the species of this family, which he 

 had found to be generally distasteful to birds, &c." 



