PLANT LICE INJURING THE FOLIAGE 199 
and known there as the “green peach aphis.’’ The lice migrate 
in early summer to various truck crops, especially spinach, cab- 
bage, lettuce, and celery. They are light green or yellowish in 
color, with darker markings on the abdomen. The head, antenne, and 
honey tubes are black. This species is never covered with white 
powdery secretion, like the eabbage aphis. It is controlled by spraying 
with a contact insecticide, preferably tobacco extract or 5 per cent 
kerosene emulsion. In greenhouses this species is found throughout 
the vear, and is a troublesome pest. 
The Melon Aphis, or Cotton Aphis (Aphis gossypii Glov.) 
Melons, cucumbers, cotton, strawberries, and many other plants 
are subject to infestation by this species of plant louse. It usually is 
seen in the wingless form, and 
works for the most part on 
the under surface of the leaf, 
which is badly curled by its 
attack. Tender growing 
shoots are a favorite feeding 
place. 
The wingless louse is dark 
green, varying to yellow. Its 
legs are light yellow, and its 
honey tubes are black, long, 
and tapering. Its length is 
one fifteenth of aninch. The 
young stages are similar, but 
are smaller and wingless. 
Winged individuals are de- 
veloped whenever the lice are 
compelled, through lack of 
food or removal of a crop, to 
Fic. 248.— Work of the Melon Aphis. 
: : Original. 
seek new feeding ground. 
Consequently attack may come on suddenly and unexpectedly. The 
full life round is not known, and probably the species passes one 
