And now the prosaic entomologist proceeds to supplant fact for fancy.
This gall-fly is a sort of cousin to the wasps, but what we would call
its sting is more than a mere sting. Like a sting, it seems to
puncture the bark or leaf, and at the same time probably to inject its
drop of venom; but at the same time it conveys to the depths of the
wound a tiny egg, or perhaps a host of them. One gall-fly is thus a
magician in chemistry, at least, for no sooner are these eggs
deposited than the wounded branch begins to swell and form a cellular
growth or tumor about them, the character of this abnormal growth
depending upon the peculiar charm of the venomous touch--to one a tiny
coral globe, to another a cluster of spines, to another a curved horn,
and to our cynips of the white or scrub oak a peculiar globular,
spongy growth which completely envelops the stem, sometimes to the
size of a small apple. In its prime it is a beautiful object, with its
fibrous, glistening texture studded with pink points. But this
condition lasts but a few days, when the entire mass becomes brownish
and woolly, which fact has given this insect the common name of
"wool-sower."
And now we must lose no time if we would follow its history to its
complete cycle. If we put one of these faded sponges in a tight-closed
box, we shall in a few days learn the secret of its being. For this
singular mimic fruit which has sprung at the behest of the gall-fly,
like other fruits, has its seeds--seeds which are animated with
peculiar life, and which sprout in a way we would hardly expect.
Within a fortnight after gathering, perhaps, we find our box swarming
with tiny, black flies, while if we dissect the sponge we find its
long-beaked seeds entirely empty, and each with a clean round hole
gnawed through its shell, explaining this host of gall-flies, all
similar to the parent of a few weeks since, and all bent on the same
mischief when you shall let them loose at the window.
The beautiful sponge of the sweet-brier has been called into being by
exactly similar means, and its hard, woody centre is packed full of
cells, at first each with its tiny egg, and then with its plump larva,
followed by the chrysalis, and at length by the emergence of the
full-fledged _Cynips rosae_.
This sponge-gall of the rose is commonly known as the Bedegnar, and,
like all other members of its tribe, as with the familiar oak-apple,
was long supposed to be a regular accessory fruit of its parent stalk.
Among early students were many superstitions connected with the
Bedegnar, the nature of which may readily be inferred from its other
common name of "Robin's Pin-cushion."