MICROSCOPIC OBJECTS. 
aided by their feet or branchiae. These members are in almost 
incessant motion, a circumstance which renders the observation of 
their precise form in the living animal difficult. One of them is 
represented as seen under a higher magnifying power in A, fig. 3 ; 
they are generally transparent, but sometimes have a greenish- 
blue colour. 
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nearly to black. On each side of the eye are inserted the antennae, 
of which there are two pair, the superior being longer than the 
inferior. They are composed of numerous articulations, from each 
of which issue two or several hairs. In some species the sexes are 
distinguished by the form of these appendages, being straight and 
thicker, with an enlargement towards the middle of their length, 
in the male, as shown in fig. 4. 
These insects move by sudden jumps or plunges, but sometimes 
creep along the twigs of plants, in which movements they are 
