INSECT ENEMIES. 125 
three-jointed beaks, which puncture the tender foliage, 
and through which they suck out the juices of plants. 
Their eyes are round, without eyelets. Their antennze 
are long and tapering. ‘Their legs are long and slender. 
There are but two joints to their feet. Their wings are 
nearly triangular, and the upper wings, longer than the 
body, are nearly twice as large as the lower. In repose 
these wings cover the body like a steep roof. 
‘The most wonderful thing about them is the way they 
multiply. ‘The males die soon after they pair in autumn. 
The females lay their eggs on the bark near the leaf buds, 
and then die. In spring, when the leaves begin to grow, 
the eggs hatch and they begin their depredations. All 
we 
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Fig. 113.—THE GREEN APHIS. 
the young lice are wingless females. In ten or twelve 
days they attain to maturity, and by a viviparous genera- 
tion they begin to give birth to a daily increase of about 
twenty. This second generation are also wingless fe- 
males, and soon multiply by the same process as did the 
first. Thus they multiply throughout the season, with- 
out the appearance of a single male, till in autumn they 
produce a brood of both sexes, as well as the viviparous 
form already described. During the summer, some 
of the females acquire wings, and, dispersing to other 
trees, found new colonies. ‘They are generally wingless, 
but when winged, look like the males, with a black head, 
thorax, and antenne, black dots in a row along each 
