e can discern what is invisible to us. She penetrates into the
abode, remains there for a while and at last reappears to replace the
rubbish and close the door as it was at the start. The abominable deed
is done: the Mutilla's egg has been laid in another's cocoon, beside the
slumbering larva on which the newborn grub will feed.

Here are others, all aglitter with metallic gleams: gold, emerald,
blue and purple. They are the humming-birds of the insect-world, the
Chrysis-wasps, or Golden Wasps, another set of exterminators of the
larvae overcome with lethargy in their cocoons. In them, the atrocious
assassin of cradled children lies hidden under the splendour of the
garb. One of them, half emerald and half pale-pink, Parnopes carnea by
name, boldly enters the burrow of Bembex rostrata at the very moment
when the mother is at home, bringing a fresh piece to her larva, whom
she feeds from day to day. To the elegant criminal, unskilled in navvy's
work, this is the one moment to find the door open. If the mother were
away, the house would be shut up; and the Golden Wasp, that sneak-thief
in royal robes, could not get in. She enters, therefore, dwarf as she
is, the house of the giantess whose ruin she is meditating; she makes
her way right to the back, all heedless of the Bembex, her sting and
her powerful jaws. What cares she that the home is not deserted? Either
unmindful of the danger or paralysed with terror, the Bembex mother lets
her have her way.

The unconcern of the invaded is equalled only by the boldness of
the invader. Have I not seen the Anthophora-bee, at the door to her
dwelling, stand a little to one side and make room for the Melecta to
enter the honey-stocked cells and substitute her family for the unhappy
parent's? One would think that they were two friends meeting on the
threshold, one going in, the other out!

It is written in the book of fate: everything shall happen without
impediment in the burrow of the Bembex; and next year, if we open the
cells of that mighty huntress of Gad-flies, we shall find some which
contain a russet-silk cocoon, the shape of a thimble with its orifice
closed with a flat lid. In this silky tabernacle, which is protected
by the hard outer shell, is a Parnopes carnea. As for the grub of the
Bembex, that grub which wove the silk and next encrusted the outer
casing with sand, it has disappeared entirely, all but the tattered
remnants of its skin. Disappeared how? The Golden Was