Entomology. 69 
of this generation the present season were observed June 4. The 
individuals of this winged generation migrated at once to the hops, 
settled and began giving birth to the fourth generation, which con- 
sisted, as did the second, of wingless, agamic females. The fifth, 
sixth, seventh, eighth, ninth, tenth and eleventh generations fol- 
lowed, and were all composed, as was the first, of wingless agamic 
females, bringing observations in point of time down to the last 
week in August, or close to the commencement of hop-picking. 
“ The last week in August the offspring of the eleventh genera- 
tion (themselves the twelfth) showed rudimentary wings, and at 
the same time the offspring born the previous week from the still 
living females of previous generations (as far back as the fifth) also 
showed plainly that they would become winged. August 26th the 
first winged females were observed at Cooperstown, and August 
31st at Richfield Springs, the main locality for observations. Sep- 
tember 2d they had already flown in small numbers to both Dam- 
son and wild plum, and had begun to deposit larvæ, which may be 
called the normal thirteenth generation. From day to day the 
winged lice increased in numbers until on the 13th of September 
the air was literally full of them, flying from the hop fields and 
settling on every variety of plum, and upon every available plum 
leaf. They were found a mile distant from any hop plant, search- 
ing for some plum tree on which to settle and bring forth young. 
Standing in front of a plum tree and facing toward a neighbor- 
ing hop yard, Mr. Pergande observed a swarm coming from the 
hops and settling upon the plum. A most interesting point in 
this connection is the fact that none of these winged generations 
will settle and reproduce on hop. This was proven by careful 
and repeated experiment. So great were the number and so com- 
pletely were the plums in certain places covered, that many of these 
winged females were obliged to settle upon neighboring weeds, 
where they brought forth young, which, however, died after feed- 
ing a few days. 
“All of these winged individuals of the twelfth generation which 
migrated to plum up to September 28th were agamic females. 
(A few were still flying late in October.) Their young (thirteenth 
generation), however, attained full growth by this date, and proved 
to be all true sexual females, wingless. At this time the males 
were discovered. They proved to belong to the twelfth generation, 
but only to the very late and much retarded offspring of the 
retarded agamic wingless eleventh. They developed late in Sep- 
tember upon the fragments of hop vines still remaining in the hop 
fields, and became winged the last week in September, just in time 
to fly to the plum and mate with the wingless sexual females which 
became full grown at this time or a little before. Immediately 
after this mating the eggs n to be deposited, and by October 
Tth large numbers could be found without trouble on the smaller 
t and branches of plum, in and around the angles formed by 
the bnds and twigs. Each female laid from one to three eggs.” 
