FEBRUARY 18. (Sunday.)
The rain has brought forth the fire-flies, and in the evening
the hedges are all brilliant with them. In the day they seem to
be torpid beetles of a dull reddish colour, but at night they become of a
shining purple. The fire
proceeds from two small
spots in the back part of the head. It is yellow in the light,
and requires motion to throw out its radiance in perfection ; but
as soon as it is touched, the fly struggles violently, and bends
itself together with a clicking noise like the snap of a spring ;
and I understand that this effort is necessary to set it in motion.
It is sufficiently strong to turn itself upwards with a single movement, if
lying on its back. When
confined in a glass, the light
seems almost extinguished ; nothing can be discerned but two
pale yellow spots; but on being pressed by the hand it becomes
more brilliant than any emerald, and when on the wing it seems
composed of the most beautifully coloured fire.
