The Glow- Worm and Other Beetles 



well enough equipped with means of re- 

 ceiving impressions even to imagine the causes 

 which guide the creature. There is, in cer- 

 tain events, another world of the senses in 

 which our organs perceive nothing, a world 

 which is closed to us. The eye of the 

 camera sees the invisible and photographs 

 the image of the ultra-violet rays; the tym- 

 panum of the microphone hears what to us 

 is silence. A scientific toy, a chemical con- 

 trivance surpass us in sensibility. Would 

 it be rash to attribute similar faculties to 

 the delicate organization of the insect, even 

 with regard to agencies unknown to our 

 science, because they do not fall within the 

 domain of our senses? To this question 

 there is no positive reply; we have suspicions 

 and nothing more. Let us at least dispel 

 a few false notions that might occur to us. 



Does the wood guide the insect, adult or 

 larva, by its structure? Gnawed across the 

 grain, it must produce a certain impression; 

 gnawed lengthwise, it must produce a dif- 

 ferent impression. Is there not something 

 here to guide the sapper? No, for in the 

 stump of a tree left standing the emergence 

 takes place, according to the proximity of the 

 light, sometimes by way of the horizontal 

 section, by means of a rectilinear path run- 

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