TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. 15 



SECOND BROOD OP NYMPHS. 



Length of stages. — The length of the stages and of the entire nym- 

 phal period of this brood was slightly shorter than in the case of 

 first-brood nymphs. Table VIII shows that the average nymphal 

 period of second-brood nymphs was 15.8 days; the maximum, 17 

 days; the minimum, 15 days. 



Table VIII. — Length of nymphal stages of the second brood of the apple leafhopper at 



West Chester, Pa., 1915. 



SECOND BROOD, JULY AND AUGUST. 



























Aver- 



























age 



























mean 



Date 























Total 



tem- 



of 



First 



First 



Second 



Sec- 

 ond 



stage. 



Third 



Third 



Fourth 



Fourth 



Fifth 



Fifth 



nym- 

 phal 

 pe- 

 riod. 



pera- 



hatch- 

 ing. 



molt. 



stage. 



molt. 



molt. 



stage. 



molt. 



stage. 



molt. 



stage. 



ture 



for 



nym- 



























phal 



























pe- 

 riod. 



1915. 



1915. 



Days. 



1915. 



Days. 



1915.. 



Days. 



1915. 



Days. 



1915. 



Days. 



Days. 



°F. 



July 14 



July 17 



3 



July 19 



2 



July 22 



3 



July 25 



3 



July 30 



5 



16 



79.70 



July 17 



July 19 



2 



July 23 



4 



July 26 



3 



July 30 



4 



Aug. 3 



4 



17 



80.22 



Do-.. 



July 20 



3 



July 22 



2 



July 24 



2 



July 28 



4 



Aug. 1 



4 



15 



80.50 



July 20 



July 22 



2 



July 23 



1 



July 27 



4 



July 30 



3 



Aug. 5 



6 



16 



79.05 



Do... 



...do.... 



2 



July 25 



3 



July 28 



3 



...do.... 



2 



Aug. 4 



5 



15 



79.00 



Do... 



...do.... 



2 



...do.... 



3 



July 29 



4 



Aug. 1 



3 



Aug. 5 



4 



16 



79.05 



July 21 



July 24 



3 



July 28 



4 



July 31 



3 



Aug. 3 



3 



Aug. 7 



4 



17 



78.27 



July 22 



July 25 



3 



July 29 



4 



...do.... 



2 



Aug. 2 



2 



Aug. 6 



4 



15 



79.40 



July 23 



...do.... 



2 



...do.... 



4 



July 30 



1 



...do.... 



3 



Aug. 7 



5 



15 



78.56 



Do... 



July 26 



3 



...do.... 



3 



...do.... 



1 



Aug. 3 



4 



Aug. 8 



5 



16 



78.52 



Do... 



July 25 



2 



July 28 



3 



...do.... 



2 



Aug. 2 



3 



Aug. 7 



5 



15 



78.56 



Do... 



July 26 



3 



...do.... 



2 



...do.... 



2 



Aug. 3 



4 



Aug. 8 



5 



16 



78.52 



Do... 



...do.... 



3 



July 27 



1 



...do.... 



....3 



...do.... 



4 



...do... 



5 



16 



78.52 



Do... 



July 27 



4 



July 29 



2 



Aug. 1 



3 



Aug. 5 



4 

 3.2 



Aug. 9 



4 



17 



78.38 



Average 



2.6 



2.7 



2.5 



4.6 



15.8 



79.01 











SECOND BROOD OF ADULTS. 



Longevity. — In Table IX the date of death for 40 second-brood 

 adults is recorded. 



Table IX. — Longevity of second-brood adults; 40 adults placed in cage Aug. 13, 1915. 



Date of examination. 



Aug. 17 

 Aug. 23 

 Aug. 26 

 Sept. 1. 



Do. 

 Sept. 13 



Do. 



Number 

 dead. 



Date of examination. 



Sept. 16 

 Sept. 20 

 Sept. 24 

 Sept. 27 

 Sept. 30 

 Do. 



Number 

 dead. 



Escaped. 



Extent of reproduction. — Four separate experiments were made to 

 determine the number of eggs deposited by a female of the second 

 brood. Two, three, four, and five pairs of adults, respectively, were 



