SELBORNE, _March 30th_, 1771.
Dear Sir,--There is an insect with us, especially on chalky districts,
which is very troublesome and teasing all the latter end of the summer,
getting into people's skins, especially those of women and children, and
raising tumours which itch intolerably. This animal (which we call a
harvest bug) is very minute, scarce discernible to the naked eye, of a
bright scarlet colour, and of the genus of Acarus. They are to be met
with in gardens on kidney-beans, or any legumens, but prevail only in the
hot months of summer. Warreners, as some have assured me, are much
infested by them on chalky downs, where these insects swarm sometimes to
so infinite a degree as to discolour their nets, and to give them a
reddish cast, while the men are so bitten as to be thrown into fevers.
There is a small, long, shining fly in these parts very troublesome to
the housewife, by getting into the chimneys, and laying its eggs in the
bacon while it is drying; these eggs produce maggots called jumpers,
which, harbouring in the gammons and best parts of the hogs, eat down to
the bone, and make great waste. This fly I suspect to be a variety of
the _musca putris_ of Linnaeus; it is to be seen in the summer in
farm-kitchens on the bacon-racks and about the mantel-pieces, and on the
ceilings.
The insect that infests turnips and many crops in the garden (destroying
often whole fields while in their seedling leaves) is an animal that
wants to be better known. The country people here call it the turnip-fly
and black-dolphin; but I know it to be one of the _coleoptera_; the
"_chrysomela oleracea_, _saltatoria_, _femoribus posticis crassissimis_."
In very hot summers they abound to an amazing degree, and, as you walk in
a field or in a garden, make a pattering like rain, by jumping on the
leaves of the turnips or cabbages.
There is an oestrus, known in these parts to every ploughboy, which,
because it is omitted by Linnaeus, is also passed over by late writers;
and that is the _curvicauda_ of old Mouset, mentioned by Derham in his
"Physico-Theology," p. 250; an insect worthy of remark for depositing its
eggs as it flies in so dextrous manner on the single hairs of the legs
and flanks of grass-horses. But then Derham is mistaken when he advances
that this oestrus is the parent of that wonderful star-tailed maggot
which he mentions afterwards; for more modern entomologists have
discovered that singular production to be derived from the egg of the
_musca chamaeleon_; see Geoffroy, t. xvii. f. 4.
A full history of noxious insects hurtful in the field, garden, and
house, suggesting all the known and likely means of destroying them,
would be allowed by the public to be a most useful and important work.
What knowledge there is of this sort lies scattered, and wants to be
collected; great improvements would soon follow, of course. A knowledge
of the properties, economy, propagation, and, in short, of the life and
conversation of these animals, is a necessary step to lead us to some
method of preventing their depredations.
As far as I am a judge, nothing would recommend entomology more than some
neat plates that should well express the generic distinctions of insects
according to Linnaeus; for I am well assured that many people would study
insects, could they set out with a more adequate notion of those
distinctions than can be conveyed at first by words alone.