THE GEAPE LEAFHOPPEE IX THE LAKE EEIE VALLEY. 25 
EXPERIMENTS TO REAR A THIRD BROOD OF NYMPHS. 
Rearing experiments were also conducted to determine if the adults 
which transformed from the earliest hatching nymphs of the season 
would produce a second summer brood of nymphs and also if the 
adults transforming from these second-brood nymphs would mate 
and produce a third brood of nymphs. 
On July 2, 100 newly hatched nymphs, the product of overwinter- 
ing adults, were placed on the foliage of a Delaware grapevine in- 
closed in an arc-light globe cage. By July 28 a few of these nymphs 
had transformed to adults. By August 14 all of these first-brood 
nymphs had transformed to adults. On August 26 several nymphs 
of the second summer brood in the first two nymphal stages were found 
upon the foliage of the vine. On August 29 aU of the adults of the 
first brood were removed from this cage in order that there might 
be no confusion with adults transforming from the second-brood 
nymphs. On September 12 newly transformed adults of the second 
brood were found in this cage. On September 27 nearly all the 
nymphs had transformed to adults. The few remaining nymphs were 
in the last nymphal stage. By October 7 all nymphs had trans- 
formed to adults. Frequent observations were made after the ap- 
pearance of the second brood of adults in this cage, but no mating 
was observed nor did any new nymphs appear on the foliage of the 
vine. Hence it would appear that reproduction did not occur among 
the adults of the second brood during the season of 1912. A similar 
rearing experiment was made on July 3 by taking 75 of the earliest 
nymphs to hatch and placing them on a grapevine inclosed in an 
arc-light globe cage. By July 16 nearly all of the nymphs had trans- 
formed to first-brood adults. On August 15 new nymphs of the 
second brood were present. On August 2S all first-brood adults 
were removed from the cage. All of the nymphs transformed to 
second-brood adults. Although frequent examinations were made 
of this cage for the remainder of the season, there was no evidence 
of reproduction by these adults of the second brood. 
In another rearing experiment the date of transformation of adults 
of the second brood was secured. The rearings were made by taking 
nymphs of the first brood that were among the earliest of the season 
to hatch. They were nearing the last molt when they were placed 
on a Concord vine in a Riley cage on July 13. By July 16 nearly all 
of these nymphs had transformed to adults. On July 26 several 
pairs were observed mating. On August 17 a few nymphs of the 
second brood in the first and second stages were observed on the 
grape foliage. On August 2S all adults of the first brood were re- 
moved from this cage to avoid confusion with newly transforming 
adults of the second brood. A record of the dates of transformation 
of adults of the second brood is siven in Table X. 
