30 RIO DE JANEIRO. [CHAP. 11. 
(such as the crustacea, meduse, nereidz, a coralline of the genus 
Clytia, and Pyrosoma), which I have observed, the light has 
been of a weJl-marked green colour. All the fireflies, which I 
caught here, belonged to the Lampyride (in which family the 
English glowworm is included), and the greater number of spe- 
cimens were of Lampyris occidentalis.* I found that this insect 
emitted the most brilliant flashes when irritated : in the intervals, 
the abdominal rings were obscured. ‘The flash was almost co- 
instantaneous in the two 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 
uninterruptedly bright, but not so brilliant as before: local irri- 
tation with 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 inter- 
vals, and that at other times the display is involuntary. On the 
muddy and wet gravel-walks I found the larvee of this lampyris 
in great numbers: they resembled in general form the female of 
the English glowworm. ‘These larve possessed but feeble 
luminous powers; very differently from their parents, on the 
slightest touch they feigned death, and ceased to shine; nor did 
writation 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 re- 
péatedly 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, notwithstanding 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 appa- 
rently as a guide. - 
* Tam greatly indebted to Mr. Waterhouse for his kindness in namin 
ne this and many other insects, and in giving me much valuable assist- 
mee, 
