which are Animals much more nasty and mischievous, having somewhat poisonous in
their Bite, as the Swelling that follows upon it shews. The Smell of these is also ex-
tremely offensive, and that as it should seem even to Fleas ; for where there are many
Bugs Fleas are but seldom seen.
Many Sorts of Herbs, if placed about the Bed, are said to destroy, or at least drive
away Fleas ; such as Elder, Fern, Penny-Royal, Rue, Mint, Hops, Laurel, Walnut, Ars-
mart, Hellebore, &c. also the Seeds of Staves-Acre, Coriander, Flea-Wort, &cc. but without
doubt the most effectual Remedy is Cleanliness.
If you attempt to catch them, remember always to wet your Thumb and Finger with
Spittle.
An EXPLANATION of the THIRTY-THIRD PLATE
The Louse
THIS last Plate shews us the Figure of a Louse magnified to a very great Degree,
that every Part thereos may be perfectly known and distinguished : And indeed this
Creature is so transparent, that the internal Structure, Disposition, and Motion of its Bow-
cls, and their Contents, may be discerned therein much better than they can in most other
Insects.
It is represented in this Picture with its Belly upwards, grasping a Hair between its
Claws.
The Head A, somewhat resembles the Fashion of a Cone, but is a little flatted on the
upper and under Part. On each Side, just where the Head is widest, a large shining black
Eye appears, very protuberant, and encompassed with a Number of small Hairs. These
Eyes B B, are situated a little behind the Head, in the Place where the Ears of other
Creatures stand ; and where one would expect to find the Eyes, a Couple of Horns come
out C C, extending themselves in such a manner, that they defend its Eyes from being in-
jured by the Hairs through which it passes.
Our Author says, each of these Horns has four Joints, fringed as it were with small
Bristles ; and the Picture C C shews no more than that Number of Divisions ; but SWAM-
MERDAM reckons five Joints to each Horn of the Louse he describes
Swammerd, Hist, Gener, des Insect. p. 174. |
; so that either the
Lice these two Observers examined, were of a different Species, or one of them must
be mistaken.
The Head grows round and tapering from where the Horns come out to the Top of
the Snout D, which ends in a sharp Point, and seems to be a tubular Instrument where-
by the Louse sucks in the Blood of the Animal it seeds on ; it is likewise probably the
Sheath of a Peircer that serves to penetrate the Skin and make a Wound for the Blood to
issue out.
In the Position before us, there seems to be a Resemblance of Chaps or Jaws, as at the
Letters E E ; yet when placed in another View those Lines or Appearances are not discern-
able. SWAMMERDAM says, it has no Mouth that opens ; and our Author observes, that
having kept several of them in a Box for two or three Days, whereby they were become
extremely hungry, upon letting one creep on his Hand, he found that it immediately fell
to Sucking ; and though it neither seemed to thrust its Nose very deep into the Skin, nor
to open any kind of Mouth, he could plainly discern a small Current of Blood passing
directly from its Snout into its Belly ; and there appeared about A some Contrivance like
a Pump, Pair of Bellows, or Heart, which by a very swift and alternate Dilatation and
Contraction drew up the Blood from the Nose and forced it into the Body. Though he
viewed it very attentively while sucking, he could not perceive that any more of its Nose
was thrust into the Skin than the very Snout D ; nor did it give him the least Pain, not-
withstanding the Blood ran through its Head very quick and freely : Which fully proves
that Blood-Vessels are dispersed into every Part of the Skin, nay, even into the Cuticula ;
for had its whole Snout been thrust in from D to C C, it would not have amounted to the
supposed Thickness of that Tegument, the Length of the whole Nose not being more
than the three hundredth Part of an Inch.
The Thorax or Breast is covered with a thin, transparent, horny, or shelly Substance,
which did not sink or become shrivelled by the Creature's fasting, as the Covering of the
Belly did. Through this our Author could plainly distinguish that the Blood sucked from