suckling?

And then, to suppose the impossible: a Wasp discovers by chance the
operative method which will be the saving attribute of her race. How are
we to admit that this fortuitous act, to which the mother has vouchsafed
no more attention than to her other less fortunate attempts, could leave
a profound trace behind it and be faithfully transmitted by heredity? Is
it not going beyond reason, going beyond the little that is known to
us as certain, if we grant to atavism this strange power, of which our
present world knows no instance? There is a good deal to be said for
this point of view, my revered master! But, once more, arguments are
here out of place; there is room only for facts, of which I will resume
the recital.

Hitherto I had but one means of studying the operative methods of the
spoilers: to surprise the Wasp in possession of her capture, to rob her
of her prey and immediately to give her in exchange a similar prey, but
a living one. This method of substitution is an excellent expedient. Its
only defect--a very grave one--is that it subjects observation to
very uncertain chances. There is little prospect of meeting the insect
dragging its victim along; and, in the second place, should good fortune
suddenly smile upon you, preoccupied as you are with other matters
you have not the substitute at hand. If we provide ourselves with the
necessary head of game in advance, the huntress is not there. We
avoid one reef to founder on another. Moreover, these unlooked for
observations, made sometimes on the public highway, the worst of
laboratories, are only half-satisfactory. In the case of swiftly-enacted
scenes, which it is not in our power to renew again and again until
perfect conviction is reached, we always fear lest we may not have seen
accurately, may not have seen everything.

A method which could be controlled at will would offer the best
guarantees, above all if employed at home, under comfortable conditions,
favourable to precision. I wished, therefore, to see my insects at work
on the actual table at which I am writing their history. Here very few
of their secrets would escape me. This wish of mine was an old one. As
a beginner, I made some experiments under glass with the Great Cerceris
(C. tuberculata) and the Yellow-winged Sphex. Neither of them responded
to my desires. The refusal of each to attack respectively her Cleonus or
her Cricket discouraged further progress in this direction. I was wrong