THE TICK. 557 



Some of the acurl are well known to frequent cheefe ; 

 others of them attach themfelves to the legs and bodies 

 of bees, fpidets, and other infecls. The pediculus pubis 

 of Rhedi, the cow and fheep loufe, feem all to belong to 

 this tribe: The former is engendered, or at leaft multi- 

 plied, by uncleanlinefs upon the pudenda, where it is 

 more vexatious than the loufe *. 



The monoculus, or arborefcent water flea, may alfo be 

 „added to the tribe of acari f . This infeft, when viewed 

 with the affiftance of the rhicrofcope, appears to have but 

 one eye ; for, on account of the fmallnefs of the head, 

 the two feem to be joined together. Vv'^hen you view 

 thejm "lyitli a lens, however, bo.th appear, and are of a re- 

 ticulated ftrufture.- Its trunk, then alfo is feeu, fmall, 

 fliarp, and tranfparent.- 



This infeft is of a blood .red colour ; and its numbers, 

 that float on the fiirface of llagnated water, are Some- 

 times fo great,, that they give it the appearance of blood. 

 Sibammerdam mentions an inftance in which the people 

 of Leyden were greatly alarmed by this colour of the wa- 

 ter, deeming it portentous of fome great calamity. 



• flhedi Expof. t, l8. f Swammerdam, Quart, p. dd. 



