38 RIO DE JANEIRO. 



rings, but it was just perceptible first in the anterior 

 one. The shining matter was fluid and very ad- 

 hesive : little spots, where the skin had been torn, 

 continued bright with a slight scintillation, whilst 

 the uninjured parts were obscured. When the 

 insect was decapitated the rings remained uninter- 

 ruptedly bright, but not so brilliant as before : local 

 irritation with a needle always increased the vivid- 

 ness of the light. The rings in one instance retain- 

 ed 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 dis- 

 play is involuntary. On the muddy and wet grav- 

 el-walks I found the larvae of this lampyris in great 

 numbers : they resembled in general form the fe- 

 male of the English glowworm. These lai-vae 

 possessed but feeble luminous powers ; very differ- 

 ently from their parents, on the slightest touch they 

 feigned death, and ceased to shine ; nor did irrita- 

 tion excite any fresh display. I kejDt several of 

 them alive for some time : their tails are very sin- 

 gular organs, for they act, by a well-fitted conti-i- 

 vance, 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 invari- 

 ably observed, that every now and then the ex- 

 tremity of the tail was ajiplied 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 luminosus, IHig.) seemed the most 

 common luminous insect. The liffht in this case 



