tiLOW WORM, OR LAMPYRIS. 1I7 
Mother. Under the last ring of the 
abdomen there are two very small reser- 
voirs of a thick, oily fluid, which, if the 
animal is crushed, leaves a luminous 
trace, that continues to give light till it 
dries. 
Lucy. So, mamma, the glow worm 
supplies her pretty little lamp with oil, 
as we do our lamps ? 
Mother. I did not mean that the 
luminous matter is literally oil, nor that 
the light is produced by combustion, or 
burning, like the flame of a lamp ; in- 
deed it does not appear to possess any 
sensible heat. Some philosophers have 
supposed that it contains a small portion 
of phosphorus, others are of a different 
opinion, and hereafter you will read with 
pleasure their experiments and their the- 
ories. Neither have naturalists ascer- 
tained by what means the insects, that 
emit light, have the faculty of concealing 
or extinguishing it. 
I will repeat to you some pretty 
