"I was in the habit," says a writer on the Island of Jamaica, "of
enclosing, every night, a dozen or more fire-flies under an inverted
glass tumbler on my bedroom table, the light of whose bodies enabled me
to read without difficulty. They are about the size of a bee, and
perfectly harmless. Their coming forth in more than usual numbers is
the certain harbinger of rain; and I have frequently, while travelling,
met them in such numbers that, be the night ever so dark, the path was
as visible as at noonday."