20 BULLETIX 19, U. S. DEPARTMENT OF AGRICULTURE. 
Several additional experiments were conducted in the same manner 
to determine the number of eggs per female. In each case several 
copulating pairs of leafhoppers were placed in each cage. 
Table III. — Experiment to determine extent of reproduction from four pairs of copu- 
lating grape leafhoppers placed in a cage with a small grapevine June 19. 1912. 
Nymphs 
1912. removed. 
July 27 154 
July 30 159 
Aug. 22 8 
Aug. 27 30 
Aug. 29 159 
Total 510 
Average 127. 5 
Table IV. — Experiment to determine extent of reproduction from nine pairs of copu- 
lating grape leafhoppers placed in a cage with a small grapevine June 18. 1912. 
Nymphs 
1912. removed. 
July 24 230 
July 31 423 
Aug. 12 172 
Aug. 22 131 
Aug. 29 65 
Sept . 4 14 
Total : 1. 035 
Average 115 
Table V. — Experiment to determine extent of reproduction from four pairs of copulating 
grape leafhoppers placed in a cage with a small grapevine June 19. 1912. 
Nymphs 
1912. removed. 
July 24 185 
Aug. 9 153 
Aug. 23 58 
Sept. 6 52 
Total 448 
Average 112 
These experiments show that for 20 females the number of nymphs 
found ranged from 112 to 139 per female. This method of deter- 
mining the egg-laying capacity of the females did not, of course, 
take into consideration the number of eggs that failed to hatch, or 
the number of fatalities which may have occurred among the nymphs 
after the hatching period, but the fact that the average number of 
nymphs reared from each of 15 females varied only from 112 to 115 
would indicate that under favorable conditions a female may deposit 
over a hundred eggs, while the 139 nymphs obtained in cage 2 would 
indicate that under the most favorable conditions some females may 
deposit about 140 eggs. 
