86 BULLETIN 903, IT. S. DEPARTMENT OF AGRICTLTrRE. 
other deposited two eggs, on September 2S and 29, respectively. 
These hatched in 11 days, the resultant larva? obviously being 
radicicoles but surviving only a few days. The third individual 
matured November 1. and between this date and November 10 it 
deposited 10 eggs. After this it became weak, and on November 16 
was mounted on a slide. The eggs were exactly similar to those laid 
by wingless radicicoles. and two of them measured, respectively. 
0.310 by 0.166 mm. and 0.297 by 0.168 mm. Seven eggs were trans- 
ferred for observation to another root, and three eggs hatched in 
from 11 to 16 days, the resultant larvas settling down for hibernation. 
One of these soon died, but the other two passed the winter in due 
form, and matured in April. 1916. Both of them were typical 
radicicoles and subsequently deposited many eggs. 
In Italy Grassi and his assistants found that the great majority 
of the intermediates were parthenogenetic. but one individual was 
found to contain a sexed egg. In discussing the phenomenon of the 
intermediates, they gave it as their opinion that the parthenogenetic 
individuals were those which up to their third stage were destined 
to become radicicoles. but in that stage changed their development 
to that of winged migrants, while the character of their eggs had 
been already fixed before the change and so remained parthenogene- 
tic. In the case of sexuparous intermediates the change was made 
in the reverse direction, the larvae at first being destined to become 
migrants and. therefore, when they matured as nymphicals they 
deposited sexed eggs. 
In California the recorded eggs laid by nymphicals were all par- 
thenogenetic. but the possibility of some of such eggs being sexual is 
not entirely excluded, in the writers* opinion. 
The nymphicals do not leave the roots in the manner of the 
winged insects, and therefore deposit their ova on the roots. In the 
ea^e of sexuparous nymphicals. the sexes and winter egg would 
presumably develop underground. Whether in California such a 
development occurs or not can not be stated from our present knowl- 
edge, but in view of the fact that for many years the leaf galls have 
been unknown, it appears certain that such a cycle proceeds no 
further than the winter egg. 
DEPOSITION OF THE SEXUAL EGGS. 
The migrants deposit eggs (PL Till. /. 7i. i) which are of two 
kinds, viz. male and female, and from these eggs issue the true sexual 
aphids. Sexual eggs have never been found by the writers in the 
vineyard, either on viniferae or on resistant vines, although a large 
number of vines have been examined. In laboratory experiments a 
large number of sexed eggs have been produced. Considerable dis- 
cussion has taken place among European writers as to the normal 
