so great that Colonel Montague, who was one of the first to describe it
minutely[2], says its speed exceeds that of any known insect, and as its
joints are so flexible as to yield in every direction (like what
mechanics call a "ball and socket"), its motions are exceedingly
grotesque as it tumbles through the fur of the bat.

[Footnote 1: This extraordinary creature had formerly been discovered
only on a few European bats. Joinville figured one which he found on the
large roussette (the flying-fox), and says he had seen another on a bat
of the same family. Dr. Templeton observed them in Ceylon in great
abundance on the fur of the _Scotophilus Coromandelicus_, and they will,
no doubt, be found on many others.]

[Footnote 2: Celeripes vespertilionis, _Mont. Lin. Trans_, xi. p. 11.]

To enable it to attain its marvellous velocity, each foot is armed with
two sharp hooks, with elastic pads opposed to them, so that the hair can
not only be rapidly seized and firmly held, but as quickly disengaged as
the creature whirls away in its headlong career.

The insects to which it hears the nearest affinity are the
_Hippoboscidæ_ or "spider flies," that infest birds and horses, but,
unlike them, it is unable to fly.

Its strangest peculiarity, and that which gave rise to the belief that
it is headless, is its faculty when at rest of throwing back its head
and pressing it close between its shoulders till the under side becomes
uppermost, not a vestige of head being discernible where we would
naturally look for it, and the whole seeming but a casual inequality on
its back.