290 T. H. Morgan 
localities the proportion of wingless and winged forms varies 
widely. Local races or local conditions may be the cause of 
this variation, and near New York and near Stamford, Conn., the 
cycle is intermediate between that described by Walsh and that 
given by Pergande. 
LIFE-CYCLE IN PHYLLOXERA CARYZCAULIS 
As stated on a preceding page the life-cycle of this species 1s 
typical. When the gall is mature it cracks open and allows 
the winged individuals to escape. ‘These fly out and those that 
alight on the leaves deposit their eggs on the under surface of 
the leaves along the midrib, especially near the base. Hundreds 
of eggs, large and small, may be found on the same leaf. A count 
of eggs from the leaves showed large female eggs and small male 
eggs approximately in the proportion of one to five. ‘The data 
obtained in this way are open to some objection, because if the 
male layers should escape from the galls first, there would be 
at first a disproportionately high male rate. Or if the male layers 
were more active fliers, they might scatter more widely and more 
of them fail to reach the leaves of the trees from which they came. 
Again if the males hatch sooner than the females, proportionately 
too few male eggs would be left on the leaves. For perfectly 
accurate data the counts should be made throughout the migra- 
tion period and this I have been unable to do. “Nevertheless I 
think the proportions given above represent an approximately 
true estimate. 
Of far greater importance are the counts of the male producing 
and female producing inhabitants of each gall, as these are all the 
offspring of the same stem-mother, herself the product of a winter 
egg, fertilized by a “female producing” spermatozoon. ‘The galls 
had been placed in Carnoy solution'® and preserved in 95 per cent 
alcohol. ‘They were opened and their inmates placed in absolute 
alcohol and then in xylol, and examined under the microscope. 
10 Equal parts of absolute alcohol, glacial acetic acid and chloroform, saturated with corrosive sub- 
limate. 
