150 APTERA. 



origin of the tail, where they are collected in 

 two oval packets, one on each side, in the shape 

 of a bunch of grapes. This is particularly ob- 

 servable in the M, qiiadricornis y a diminutive 

 insect not much larger than a mite, which has 

 sometimes been brought to table in our spring- 

 water. The female, with her long forked tail 

 and bunches of little grapes, may be seen spring- 

 ing about in the water with great agility. These 

 bunches of eggs they never part with till the 

 young are hatched. The species which is by 

 far the most common, and the most familiar to 

 the unscientific observer, is the M. Pulex, or 

 Water-flea. This is found in ponds, ditches, 

 &c. at all seasons of the year, and in warm 

 weather in such abundance, as often to discolour 

 the water it inhabits. Its appearance is very 

 singular w T hen examined by the microscope ; 

 its body being inclosed in a bivalve sheath, 

 from the opening of which proceeds its forked 

 leg. The horns are branched in a peculiar 

 manner, and the insect can move them in all 

 directions, so as to contribute materially by 

 their action, to that jerking motion in the 



