756 RosBert MATHESON 
to those of the winged female. The length of the antennal segments 
and the number of sensoria are as follows: Segment III, 0.24 mm., sen- 
soria 14; Segment IV, 0.12 mm., sensoria 3; Segment V, 0.12 mm., sensoria 
2; Segment VI, 0.8 + 0.35 mm., sensoria the usual group. 
Oviparous female (Plate XXIX).— The oviparous female is from 1 to 1.3 
mm. long. It is distinctly elongate-oval in outline. The general color 
is yellowish green, shading more or less to brownish green or in some 
cases to almost green; the antennae and the legs are somewhat brownish; 
the cornicles are short, brown to almost black; frequently there is an 
orange-colored or reddish yellow area around the base of the cornicles, 
but this may be absent in older specimens. The cornicles are cylindrical, 
constricted before the apex, which is markedly flared (fig. 117, 8B, page 714). 
The hind tibiae are somewhat enlarged and flattened, and bear from 29 
to 32 sensoria (fig. 119, B, page 716). The cauda is distinct, tapering, 
bordered with three pairs of hairs. The length of the antennal segments 
(fig. 118, c, page 715) and the number of sensoria are as follows: Seg- 
ment III, 0.18 mm., sensoria 0; Segment IV, 0.094 mm., sensoria 1; 
Segment V, 0.053 + 0.22 mm., sensoria the usual group. 
The egg is oval in form, and is slightly flattened on the side next the 
bark. Its length is from 0.48 to 0.56 mm. In color it is identical with 
the egg of Aphis pomi. 
EFFECTS OF ATTACKS OF PLANT LICE ON THE APPLE TREE AND ITS FRUIT 
THE GREEN APPLE APHIS 
The work of the species Aphis pomi is very characteristic and is easily | 
distinguished from that of the other two species, A. sorbz and A. avenae. 
As soon as the apple buds begin to open, the lice congregate on the tips 
of the leaves and soon penetrate deep into the unfolding buds, inserting 
their beaks and sucking out the juices. They particularly attack the 
leaves and the flower stalks, and as soon as the tender shoots (Plate VII), | 
especially the water shoots, form, they crowd in dense masses on these, | 
frequently killing them outright. In these dense crowds of lice on the water. 
shoots Aphis avenae also may be present, at least early in May, but A. 
sorbi is not present. 
Aphis pomi is also a leaf-attacking form, and is generally found on the 
under surface of the leaf crowded about the midrib and the lateral veins. 
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