her to make
underground searches. When she has found the propitious place, suddenly
she will swoop down, lay her egg on the surface in that lightning
touch with the tip of her abdomen and straightway fly up again. What I
suspect, for reasons set forth presently, is that the grub that comes
out of the Bombylius' egg must, of its own motion, at its own risk and
peril, reach the victuals which the mother knows to be close at hand.
She has no strength to do more; and it is for the new-born grub to make
its way into the refectory.

I am better acquainted with the manoeuvres of certain Tachinae, the
tiniest of pale-grey Flies, who, cowering on the sand in the sun, in the
neighbourhood of a burrow, patiently await the hour at which to strike
the fell blow. Let a Bembex-wasp return from the chase, with her
Gad-fly; a Philanthus, with her Bee; a Cerceris, with her Weevil; a
Tachytes, with her Locust: straightway the parasites are there, coming
and going, turning and twisting with the Wasp, always at her rear,
without allowing themselves to be put off by any cautious feints. At the
moment when the huntress goes indoors, with her captured game between
her legs, they fling themselves on her prey, which is on the point of
disappearing underground, and nimbly lay their eggs upon it. The thing
is done in the twinkling of an eye: before the threshold is crossed,
the carcase holds the germs of a new set of guests, who will feed on
victuals not amassed for them and starve the children of the house to
death.

This other, resting on the burning sand, is also a member of the
Fly tribe; she is an Anthrax. (Cf. "The Life of the Fly": chapter
2.--Translator's Note.) She has wide wings, spread horizontally, half
smoked and half transparent. She wears a dress of velvet, like the
Bombylius, her near neighbour in the official registers; but, though
the soft down is similar in fineness, it is very different in colour.
Anthrax is Greek for coal. It is a happy denomination, reminding us of
the Fly's mourning livery, a coal-black livery with silver tears. The
same deep mourning garbs those parasitic Bees, and these are the only
instances known to me of that violent opposition of dead black and
white.

Nowadays, when men interpret everything with glorious assurance, when
they explain the Lion's tawny mane as due to the colour of the African
desert, attribute the Tiger's dark stripes to the streaks of shadow cast
by the bamboos and extricate any nu