THE GEAPE LEAFHOPPEK IN THE LAKE ERIE VALLEY. 19 
NUMBER OF EGGS DEPOSITED BY AN OVERWINTERING FEMALE GRAPE 
LEAFHOPPER. 
On account of the great difficulty encountered in locating the eggs 
of the grape leafhopper, a record of the reproductive capacity of the 
females was secured by confining pairs of overwintering adults upon 
small grapevines in an arc-light globe cage similar to that shown in 
Plate II, figure 1 , which had been protected from previous infestation, 
the object being to determine the number of nymphs that appeared 
on the vines. The pairs used for this purpose were among the first 
to be found copulating and at a period before any oviposition had 
taken place. Each pair of adults was allowed to remain on the 
vine until they died. To avoid the probability of the escape of the 
adults, only a few examinations were made until the nymphs were 
nearing the last molt. The parent adults were then removed and a 
careful count was made of the nymphs found upon the foliage; then 
the parent adults were returned to the cage until later examinations 
were made, and this process was continued until the death of the par- 
ent adults occurred. After the death of the adults a period equal to 
the length of incubation of the eggs was allowed to elapse before the 
final count for the last nymphs to appear was made. Four separate 
experiments were started May 27 with copulating pairs of adults. 
Removal of nymphs took place as shown in Table II. 
Table II. — Number of nymphs produced by a female grape leafhopper in confinement. 
Nymphs 
1912. CAGE XO. I. removed. 
July 11 34 
July 17 33 
July 2 5 36 
Total 103 
CAGE XO. II. 
July 11 49 
July 17 I 49 
July 25 33 
Aug. 1 8 
Total 139 
CAGE XO. III. 
July 10 _ . . . . 14 
July 11 * . . . . 56 
July 17 34 
July 25 _ 18 
Aug. 1 1 
Total 113 
CAGE XO. IV. 
July 11 34 
July 17 33 
July 25 '. 36 
Aug. 1 9 
Aug. 2 2 
Total 114 
1 Four newly molted adults. 
