been fubdivided into different genera on account of 
the difpofition of the eyes, which in fome fpecies 
are approximated, fo as to appear as if lingle, while 
in others they are remote from each other. It muff 
be confeffed that the title Monoculus is, with refpeeff 
to many of the fpecies, rather an unfortunate one ; 
yet fince the infedts which Linnaeus has arranged 
under the genus agree fufficiently in the general 
ftrudture of their feveral parts, it feems better to 
continue it as it firft flood, than to create confufion 
by the unneceffary inflitution of new genera; a fault 
which feems to be prevailing among modern ento- 
mologifts. The Monoculus apus is generally of a 
greenifh cafl, and fometimes of a reddifh or pale 
brown. It is rare in comparifon with many other 
fpecies, and is found in large ponds and other ftag- 
nant waters. The plate reprefents it in its natural 
fize. In the Philofophical Tranfa&ions may be 
found a good figure of this infedl, with a deferip- 
tion by Klein, from a fpecimen found in Germany; 
to which is added an account of the fame animal 
difeovered in great plenty in a pond on Bexly com¬ 
mon in Kent. It is alfo added that the above-men¬ 
tioned pond having been perfectly dried, and being 
fuddenly filled during a heavy thunder-ftorm, fwarms 
of the fame animal were again observed in it within 
the fpace of two days. 
