The Glow-worm 
91 
the rest of the body and would seem to 
indicate by their colouring that portion 
of the body which is luminous. The 
luminous property of the glow-worm is 
quite under its control, as it is able, when 
disturbed or alarmed, to extinguish the 
light in a moment, though they will not 
always do so even when picked up. I have 
carried them sometimes in the palm of my 
hand for quite a long distance, while the 
light has been kept fully burning. It is 
often taken as a sign of rain when many 
of these little luminous patches are to be 
seen in the hedgerows and banks. Their 
cousins, the fire flies, are as a rule most 
brilliant when a storm is coming. On one 
occasion abroad, I saw a whole country 
side rendered quite light with numberless 
fire flies, and this display was succeeded 
by twelve hours of torrential rain. To 
a degree the eggs, larvae and pupae, 
resemble the female, in that they have a 
slight luminosity, while even in the case of 
the male beetle, the faintest light may 
sometimes be seen. In the larval state 
these insects are most useful. They possess 
very strong mandibles or jaws, and are 
