To escape falling into this twofold trap, the theorists will reply that the
Scoliae are descended from a precursor, an indeterminate creature, of
changeable habits and changing form, modifying itself in accordance with
its environment and with the regional and climatic conditions and branching
out into races each of which has become a species with the attributes which
distinguish it to-day. The precursor is the deus ex machina of evolution.
When the difficulty becomes altogether too importunate, quick, a precursor,
to fill up the gaps, quick, an imaginary creature, the nebulous plaything
of the mind! This is seeking to lighten the darkness with a still deeper
obscurity; to illumine the day by piling cloud upon cloud. Precursors are
easier to find than sound arguments. Nevertheless, let us put the precursor
of the Scoliae to the test.

What did she do? Being capable of everything, she did a bit of everything.
Among its descendants were innovators who developed a taste for tunnelling
in sand and vegetable mould. There they encountered the larvae of the
Cetonia, the Oryctes, the Anoxia, succulent morsels on which to rear their
families. By degrees the indeterminate Wasp adopted the sturdy proportions
demanded by underground labour. By degrees she learnt to stab her plump
neighbours in scientific fashion; by degrees she acquired the difficult art
of consuming her prey without killing it; at length, by degrees, aided by
the richness of her diet, she became the powerful Scolia with whom we are
familiar. Having reached this point, the species assumes a permanent form,
as does its instinct.

Here we have a multiplicity of stages, all of the slowest, all of the most
incredible nature, whereas the Wasp cannot found a race except on the
express condition of complete success from the first attempt. We will not
insist further upon the insurmountable objection; we will admit that, amid