5 2 Of Lice. 
at the extremity of the tail are two femieircular parts 
covered all over with hair. 
Place a loufe on its back and two darkifh bloody fpots 
will appear: the larger in the middle of the body, and 
the leffer towards the tail. In the larger fpot a white 
Him ’ J or bladder contra&s, and dilates upwards and 
downwards from the head towards the tail $ the pulfe of 
which is followed by a pulfe of the dark bloody fpot, in 
or over which the white bladder feems to lie. This 
motion of fyflole and diaftole is feen belt when the loufe 
is grown weak 5 the white pulfing bladder feems to be 
the heart, for on pricking it the loufe inflantly dies. The 
lower darkifh fpot is thought to be the excrement in 
the guts. 
The males have flings x in their tails, the females 
none : the females lay eggs or nits, from whence lice are 
produced perfect in all their members, and undergo no 
farther change. 
Mr. Leeuwenhoek obferved that in fix days one of 
them had laid fifty eggs, and differing it, he faw as 
many more in the ovary; concluding from thence that it 
would have laid an hundred eggs in twelve days. Thefe 
eggs hatched in fix days, would probably produce fifty 
males and as many females ; and thefe females coming to 
their full growth in eighteen days, might in twelve days 
more probably lay an hundred eggs alfo, which eggs 
In fix days farther, the time required to hatch them, might 
produce a young brood of five thoufand ; fo that in eight 
weeks a loufe may fee five thoufand y of its own de¬ 
fendants* 
Upon 
“ Power’s Micro. Obf. p. 9. x Arc. Nat. Tom. ii. p. 77. 
v Ibid. p. 77. * Arc. Nat, Tom. i. p. 78, 
