98 On the Pho/phorefeence of the Luciolé: 
The light of the luciole does not depend on the influence 
of any external caufe, but merely on the will of thefe infects, 
While they fly about at freedom their fhining is very 
regular; but when they are once in our power, they fhine 
very irregularly, or do not fhine at all. When they are 
molefted they emit a frequent light, which appears to be a 
mark of their refentment. When placed on their backs 
they fhine almoft without interruption, making continual 
efforts to turn themfelves from that pofition. In the day- 
time it is neceflary to torment them in order to make them 
fhine, and thence it follows that the day to them is the fea- 
fon of repofe. The luciole emit light at pleafure from every 
point of their bellies, which proves that they can move all 
the parts of their vifcera independently of each other. 
They can alfo render their phofphorefcence more or lefs 
vivid, and continue it as long as they pleafe. 
The faculty of fparkling does not ceafe on their bellies 
being torn, or opened by an incifion. Carradori faw part 
of the belly of one feparated from the reft of the body, the 
light of which was almoft extinguifhed, grow luminous all 
of a fudden for fome feconds, and afterwards become 
gradually extin&. He fometimes faw a like portion, which 
had been feparated, pafs fuddenly from the moft brillant 
ftate to that of total darknefs, and afterwards refume its 
former brightnefs. Carradori afcribes this phenomenon te 
a remainder of irritability, or a flimulus produced by the . 
air, which appears the more probable, as a mechanical irri- 
tation produced the fame effect. 
A flight compreffion deprives the luciole of their power 
of ceafing to fhine. The author is inclined to believe that 
the movement by which they conceal their light, is executed 
by drawing back their phofphoric fubftance into a particular 
membrane or tunic. He fuppofes alfo that the fparkling © 
‘confifts in a trembling or ofcillation of the phofphoriec maf. 
He is of opinion that there is no emanation of, a phofphoric 
fubftance, and that the whole phenomenon takes place in 
the 
