_(For the Mirror.)_
These extraordinary little insects are more particularly noticed in Italy,
during the period of summer, than in any other part of the world. When
they make their appearance, they glitter like stars reflected by the sea,
so beautiful and luminous are their minute bodies. Many contemplative
lovers of the phenomena of nature are seen, soon after sun-set, along the
sea coast, admiring the singular lustre of the water when covered with
these particles of life, which it may be observed, are more numerous where
the _alga marina_, or sea-weed abounds.
The marine glow-worm is composed of eleven articulations, or rings; upon
these rings, and near the belly of the insect, are placed fins, which
appear to be the chief instruments of its motion. It has two small horns
issuing from the fore part of the head, and its tail is cleft in two. To
the naked eye of man, they seem even smaller than the finest hairs; and
their substance is delicate beyond description. They first begin to make
their appearance upon the sea-weed about the middle of April, and very
soon after multiply exceedingly over the whole surface of the water.
I think it is more than probable, that the heat of the sun causes the
marine glow-worm to lay its eggs; at all events it is certain, that
terrestrial insects of this species shine only in the heat of summer, and
that their peculiar resplendency is produced during the period of their
copulation.