GENERIC CLASSIFICATION OF APHIDIDAE. 3 
PHYLOGENY OF THE APHIDIDAE. 
In many published classifications of the Aphididae those groups 
which according to the writer's conception are the most specialized 
have been placed as the most primitive. This is the case with those 
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Fig. 1. — Phylogeny of the hemipterous family Aphididae. 
insects forming in the present classification the Eriosomatinae and 
the Hormaphidinae. 
A study of the anatomy and the biology of aphids makes it evident 
that there are three main groups of living forms for which subfamily 
