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4a OTHER LUMINOUS INSECTS, [chap, 



bright, but not so brilliant as before : local irritation 

 a needle always increased the vividness of the light. The 

 rings in one instance retained their luminous property 

 nearly twenty-four hours after the death of the insect. 

 From these facts it would appear probable, that the animal 

 has only the power of concealing or extinguishing the light 

 for short intervals, and that at other times the display is 

 involuntary. On the muddy and wet gravel-walks I found 

 the larvae of this lampyris in great numbers : they 

 resembled in general form the female of the English 

 glowworm. These larvae possessed but feeble luminous 

 powers ; very differently from their parents, on the slightest 

 touch they feigned death, and ceased to shine ; nor did 

 irritation excite any fresh display. I kept several of them 

 alive for some time : their tails are very singular organs, 

 for they act, by a well-fitted contrivance, as suckers or 

 organs of attachment, and likewise as reservoirs for saliva, 

 or some such fluid. I repeatedly fed them on raw meat 

 and I invariably obse.rved, that every now and then tl 

 extremity of the tail was applied to the mouth, and a drc 

 of fluid exuded on the meat, which was then in the 

 of being consumed. The tail, notwithstanding so mud 

 practice, does not seem to be able to find its way to the 

 mouth ; at least the neck was always touched first, anj 

 apparently as a guide. 



When we were at Bahia, an elater or beetle {Pyrophc 

 luminosus, Illig. ) seemed the most common luminous insect. 

 The light in this case was also rendered more brilliant by 

 irritation. I amused myself one day by observing the 

 springing powers of this insect, which have not, as it 

 appears to me, been properly described. The elater, when 

 placed on its back and preparing to spring, moved its head 

 and thorax backwards, so that the pectoral spine was 

 drawn out, and rested on the edge of its sheath. The 

 same backward movement being continued, the spine, 

 by the full action of the muscles, was bent like a spring ; 

 and the insect at this moment rested on the extremity of 

 its head and wing-cases. The effort being suddenly relaxed, 

 the head and thorax flew up, and in consequence, the base 

 of the wing-cases struck the supporting surface with such 

 force, that the insect by the reaction was jerked upwards 

 to the height of one or two inches. The projecting points 

 of the thorax, and the sheath of the spine, served to steady 



* Kirby's " Entomology," vol. u., p. 317. 



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