1832.] PHOSPHORESCENT INSECTS. 29 



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 larva 1 

 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 

 observed, that every now and then the extremity of the tail was 

 applied to the mouth, and a drop of fluid exuded on the meat, 

 which was then in the act of being consumed. The tail, notwith- 

 standing so much practice, does not seem to be able to find its way 

 to the mouth ; at least the neck was always touched first, and 

 apparently as a guide. 



When we were at Bahia, an elater or beetle (Pyrophorus lunii- 

 nosus, 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 the whole body 

 during the spring. In the descriptions which I have read, suf- 

 ficient stress does not appear to have been laid on the elasticity 

 of the spine: so sudden a spring could not be the result of 

 simple muscular contraction, without the aid of some mechanical 

 contrivance. 



* Kirby'a Entomology, vol. ii. p. 317. 



