The. HAS T OR Y Of TINDS PC Tis; Q 
Fre. II. 
Th eegg-/hell, or empty Nit, and the firft shin 
caft by the Loufe. 
a. The border or extremity of the head burft 
‘afunder with its little cups, and driven back 
by the Loufe creeping out at the upper end. 
6. The other part of the caft and empty 
fin of the Nit, from which the border of the 
head was feparated; fo that it refembles an 
empty tankard, having its aperculum or cover 
taken off. 
apdeiG. «lll, 
The Loufe hing on its belly, and magnified with 
the nucrofcope. 
On its head is feen a fhining fkin, together 
with fome little holes and divifions. On the 
39 
breaft or back is an elegant delineation of a 
fhield, which is painted in the middle; and 
the glittering fkin is alfo obferved to be here 
variegated with little holes. The legs, which 
are fixed to the breaft, are full of little {wellings 
or pimples, like fhagreen fkin, but they are 
loft by degrees towards the end of the legs. 
There are many hairs betweeen the claws of 
the legs. It hath been difcovered by the mi- 
crofcope, that at the extremity of the abdomen, 
the skin likewife appears painted and rugged, 
with little grains like fhagreen as before men- 
tioned; but I have at length difcovered with 
the beft microfcope, that the skin really confifts 
of irregular {quares, globules, &c. 
Of the Arborefcent Water Flea *. 
fter the Loufe I have likewife in this firft 
order, placed the Arborefcent Flea, whereof 
I now intend to treat particularly. ‘This infect, 
which I here delineate larger than the life, 
Tab. XXXI. fig. 1. a. is the fame that in fig, 
11. I have reprefented alfo larger, yet ina fide 
view. In this, befides the outward form of 
the body, which is {quare as it were, I thew 
an eye in one fide of the head, fig. 11. 2. and un- 
der ita fharp beak c. On the breaft are feen 
arms, divided into branches 44 like the boughs 
of trees; and in the abdomen there is a 
tran{parent fubftance, with the legs and tail ; 
and in the hinder part of the body, \Jits legs 
appear placed as it were on the middle of the 
back. 
But if this animal be reprefented in the 
form wherein it fhews itfelf to the naked 
fight, you would fay it had only one eye; for 
the eyes, by reafon of the fmallnef$ of the 
head, feem to be joined to each other. They 
are fituated in the beak of this infeét, and this 
beak is likewife very fmall and fharp-pointed, 
The ftructure of the eye is feen by the micro- 
{cope, to be reticulated, or made like a net, fuch 
as we fee in the eyes of other infeéts, and the 
beak is not only {mall and fharp, but alfo 
tranfparent: and it feems probable, that this 
little animal fucks in its food, by the help of 
‘this little part, as is ufual with other aquatic 
infects, which feed themfelves with their 
hollow beak, or tubular aculeus or fucker. 
Of all the parts of this animal, its branching 
arms, and the motion it makes with them in 
the water, deferve out greateft attention, ‘They 
arife undivided from two, as it were, fimple 
trunks, which, like the fhoulder bones, {pring 
from the fhoulder blades, and are each divided 
into two branches; each of thefe is again fub- 
divided into three different joints. At the firft 
,and fecond joint, reckoning from the fingle 
“trunk, there arife on each fide a little branch, 
almoft like a hair ; and at the third or extreme 
joint, three {uch buds or fhootings are placed, 
which alfo feem to be again divided into other 
joints. 
But though thefe arms are very remarkable, 
and worthy of confideration, the motion pro- 
duced with them by this infeét deferve yet 
greater notice. or this is threefold; firft, the 
little creature can, with their affiftance, move 
in a ftraight line ; whilft it conftantly waves its 
ramified arms, as a bird its wings in the air, 
fometimes upward, fometimes downward, and 
fometimes on one fide, and all the while moves 
forward in a ftraight line. | 
A fecond motion is like that of the fparrow, 
for as thiefe, by expanding and again contracting 
their wings, pafs with an uneven motion 
through the air, and fometimes defcend, and 
immediately after are carried aloft again; fo 
this little animal, by ftriking the water now and 
then with its branching arms, obtains a like 
unequal motion, and fometimes dives as it 
were to the bottom, and again rifes up to the 
furface. ‘Thefe arife from the alternate ceafing 
and repetition of the motion; the animal by 
this means moving ina different manner. Since, 
therefore, the motion of this little creature is 
not at that time very irregular, it happens that 
it is continually feen to jump in the water, its 
head always tending towards the furface, and 
its tail ftretched downward. 
I cannot find a more proper example of the 
third kind of motion in this animal, than the 
whirling or turning about of that kind of 
pidgeons, which, from this whirling or gyration 
of the body, are called tumblers. For as thefe 
tumblers, when whirled about in the air like 
a ball, feem for a time to be deprived of their 
motion, and fall as it were downward towards 
the earth; fo this little creature, inclining its 
head down into the water, and at the fame 
time raifing the hinder part of its body upwards, 
moves itfelf as it were in a circle, without any 
interruption in the motion of its arms, which 
it ufes upon this occafion as oars. Hence it 
happens, that the parts of its body, though in 
perpetual motion, and naturally always funk 
into the watcr, are fometimes feen under and 
fometimes above it; which is a very pleafant 
® This infe@ is frequent with us in fhallow and ftanding waters, asin the ditches at Tothill-felds. 
fight, 
