GRAPE DISEASE. 623 
while they are abundantly nourished, but towards winter when, by 
this mode of reproduction, and by the diminishing nutriment in 
the dying foliage, the lice become, so to speak, exhausted, then lo 
and behold winged males and females appear! Numerous other 
facts in insect life such as the production of drone bees solely from 
unfertilized eggs, etc., indicate that the winged male may be, in 
some way or other, connected with defective vitality; and Mr. 
Thomas Meehan, of the ‘‘ Gardener’s Monthly,” has so frequently 
observed such to be the case with plants, that he considers it a 
law “ that with a weakened vitality comes an increased power to 
bear male flowers.”* But this throws no light on the production 
of winged females, and here, as in thousands of other instances, 
nature tells us plainly to be satisfied with the facts without the 
explanation. 
Our winged female is a reality! What, then are her functions? 
In the breeding jars she invariably flies towards the greatest 
light, and her large compound eyes, and ample wings indicate that 
she was made for the light and the air. We have also seen that 
she is burdened with two or three eggs only, and my opinion is 
that after meeting her mate, her sole life duty is to fly off and con- 
sign her few-eggs to some grape-vine or grape-bud, and that the 
lice hatching from these eggs constitute the first gall-producing 
mothers. : 
Lam led to this opinion by the fact that about the middle of 
May, in looking for the galls, I always find but two or three to a 
vine, and generally but one to a leaf. These vernal galls, as one 
would expect from the greater vitality of the young from ferti- 
lized eggs, and the greater succulency of the leaves at that season 
are much larger than the ordinary summer form, and generally 
have a decided rosy tint on one side. Similar galls have also 
been found in France. Just as many other insects prefer certain 
Species of plants, or even certain varieties of a species, so our 
winged Phylloxera shows her preference for the Clinton and its 
close allies. She occasionally deposits her eggs on other varieties, 
as I have found the large vernal galls on Concord, Hartfo 
Prolific, ete., and it follows that she must do so where no riparia 
vines occur. But, except on the varieties of the latter species, the 
young lice hatching from her eggs do not seem to be eapable of 
at ae oe 
: *Proc. Am. Ass. Ady. Sci., 1869, p. 256. : 
