92 
iFLLETIX 903. U. S. DEPAETMEl^T OF AGRICTILTTTEE. 
the young radicicole. Caudal segment bluntly rounded. Eyes as in the radi- 
cicole larva. When the adult issues the single egg within is small, but within 
three days it becomes very evident (PI. VIII. ;) and occupies in section an area 
equal to about three-fourths of the entire insect. 
Table XXIX. — Measurements of mature sexual females of the grape phylloxera. 
1 2 
Length of bodv 
Maximum width of body 
Length of " winter" egg contained 
Maximum width of •• winter*' egg contained. 
Antennal joint 1, right, length. 
Antennal joint 1, left, length 
Antennal joint 2, right, length.. . 
Antennal joint 2, left, length 
Antennal joint 3, right, length 
Antennal joint 3, left, length 
Mm. 
Mm. 
0.357 
0.464 
.200 
.215 
. 313 
.172 
. 017 
.0200 
.016 
.0179 
.013 
. 0205 
.013 
.0188 
.054 
.0.580 
.053 
. 0553 
THE MALE. 
Dusky orange, darker than the sexed female : antenna?, legs, and genital 
segment dusky grayish : eyes of three facets each, red : beak absent. Body 
quite noticeably shorter, flatter, and narrower than that of the sexed female, 
and shorter and narrower than that of the newly hatched radicicole. Genital 
organ acutely conical. 
Table XXX. — Measurements of mature males of the grape phylloxera. 
i J/77?. 
Length of body ■ 0.260 
Maximum width of body ! . 094 
Antennal joint 1, length. .013 
Antennal joint 2, length . 018 
Antennal ioint 3. lensth ; - 065 
Hind tibia, length .046 
Hind femur, length .056 
Mm. 
0.334 
.154 
.071 
In confinement both sexes at first exhibit a positive phototropism. 
but after a day of maturity they seek shaded places. At first they 
are quite active, but later become sluggish. Undoubtedly they are 
much less active in confinement than in the natural state. 
Table XXXI summarizes the development of the sexed form in the 
summer and fall of 1911 and 1913. All those which reached the 
adult state were females. 
Table XXXI. — Summarized record of sex development of the grape phylloxera, 
Walnut Creel:. Calif., Jf'll and WIS. 
Average incubation period 
Average postembryonic period 
Average period of development 
Xumber 
of indi- 
viduals. 
12 
12 
20 
Davs. 
5.83 
11.05 
