. The grape leafhopper in the Lake Erie Valley. 4 Total : 1. 035 Average 115 Table V.—Experiment to determine extent of reproduction from four pairs of copulatinggrape leafhoppers placed in a cage with a small grapevine June 19. 1912. Nymphs1912. 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 nymphsfound 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, orthe number of fatali
. The grape leafhopper in the Lake Erie Valley. 4 Total : 1. 035 Average 115 Table V.—Experiment to determine extent of reproduction from four pairs of copulatinggrape leafhoppers placed in a cage with a small grapevine June 19. 1912. Nymphs1912. 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 nymphsfound 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, orthe number of fatalities which may have occurred among the nymphsafter the hatching period, but the fact that the average number ofnymphs reared from each of 15 females varied only from 112 to 115would indicate that under favorable conditions a female may depositover a hundred eggs, while the 139 nymphs obtained in cage 2 wouldindicate that under the most favorable conditions some females maydeposit about 140 eggs. Bui. 19, U. S. Dept. of Agriculture. Plate Fig. 1 .—Cages Used for Rearing the Grape Leafhopper, at Laboratory, NorthEast, 1912. (Original.)
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Keywords: ., bookauthorjohnsonfred, bookcentury1900, bookdecade1910, bookyear1
