THE TICK. 
557 
Some of the acari are well known to frequent cheefe ; 
others of them attach theml'elves to the legs and bodies 
of bees, fpiders, and other infefls. The pediculus pubis 
of Rhcdi, the cow and iheep loufe, feem all to belong to 
this tribe : The former is engendered, or at ledl multi- 
plied, by uncleanlinefs upon the pudenda, where it is 
more vexatious than the loufe . 
The mnnoculus, or arborefcent water flea, may alfo he 
added to the tribe of acari +. This mfeft, when viewed 
with the affiftance of the microfcope, appears to have but 
one eye ; for, on account of the fmallnefs of the head, 
the two feem to be joined together. When you view 
them with a lens, however, both appear, and are of a re- 
ticulated ftrudture. Its trunk then alfo is feen, Imall, 
fliavp, and tranfparent. 
This infeifl is of a blood red colour ; and its numbers, 
that float on the furface of flagnated water, are fome- 
times fo great, that they give it the appearance of blood. 
Swammerdam mentions an inflance in which the people 
of Leyden were greatly alarmed by this colour of the wa- 
ter, deeming it portentous of fome great calamity. 
* Rhedi Expof. t. J 8. f Swammerdam, Quart, p. 66. 
