26 



BULLETIN 805, U. S. DEPARTMENT OF AGRICULTURE. 



SECOND BROOD OF NYMPHS. 



Length of stages. — In Table XVI the length of the stages and of the 

 entire nymphal period is recorded. The average length of the 

 nymphal period was 17.7 days; the maximum, 19 days; the mini- 

 mum, 16 days. It will be noted that the length of the nymphal 

 peiiod of the second brood was much shorter and that the corre- 

 sponding temperatures were much higher than in the case of the 

 first-brood nymphs. 



Table XVI. — Length of nymphal stages of second brood of the rose leaf hopper on nursery 

 apple trees at West Chester, Pa., 1916. 



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. 



1916. 



1916. 



Days. 



1916. 



Days. 



1916. 



Days. 



1916. 



Days. 



1916. 



Days. 



Days. 



°F. 



July 21 



July 25 



4 



July 28 



3 



July 31 



3 , 



Aug. 3 



3 



Aug. 7 



4 



17 



79.72 



July 24 



July 28 



4 



July 31 



3 



Aug. 4 



4 



Aug. 6 



2 



Aug. 10 



4 



17 



80.13 



July 25 



July 27 



2 



...do 



4 



Aug. 3 



3 



...do 



3 



...do.... 



4 



16 



80.38 



Do... 



July 28 



3 



Aug. 1 



4 



Aug. 5 



4 



Aug. 7 



2 



Aug. 12 



5 



18 



80.55 



Do... 



July 31 



6 



Aug. 3 



3 



...do 



2 



Aug. 8 



3 



...do.... 



4 



18 



80.55 



July 28 



...do.... 



3 



Aug. 4 



4 



Aug. 6 



2 



Aug. 9 



3 



Aug. 15 



6 



18 



79.84 



Do... 



Aug. 1 



4 



...do 



3 



...do 



2 



...do 



3 



...do.... 



6 



18 



79.84 



Do... 



...do.... 



4 



...do 



3 



...do 



2 



Aug. 10 



4 



Aug. 16 



6 



19 



79.70 



Do... 



...do.... 



4 



Aug. 5 



4 



Aug. 8 



3 



Aug. 12 



4 



Aug. 15 



3 



18 



79.84 



July 30 



Aug. 2 



3 



Aug. 6 



4 



...do 



2 



...do 



4 



Aug. 17 



5 



18 



80.26 



Do... 



Aug. 4 



5 



...do 



2 



Aug. 10 



4 



Aug. 15 



5 



Aug. 18 



3 



19 



80.40 



Do... 



Aug. 2 



3 



...do 



4 



Aug. 9 



3 



Aug. 13 



4 



...do.... 



5 



19 



80.40 



July 31 



Aug. 5 



5 



Aug. 9 



4 



Aug. 12 



3 



Aug. 16 



4 



Aug. 19 



3 



19 



80.75 



Do... 



...do.... 



5 



Aug. 8 



3 



...do 



4 



Aug. 15 



3 



...do.... 



4 



19 



80.75 



Aug. 3 



Aug. 6 



3 



Aug. 10 



4 



Aug. 13 



3 



Aug. 16 



3 



Aug. 20 



4 



17 



80.94 



Aug. 4 



Aug. 7 



3 



Aug. 9 



2 



...do 



4 



Aug. 17 



4 



Aug. 21 



4 



17 



81.38 



Do... 



Aug. 6 



2 



Aug. 11 



5 



Aug. 15 



4 



Aug. 18 



3 



...do.... 



3 



17 



81.38 



Do... 



Aug. 8 



4 



Aug. 12 



4 



...do 



3 



Aug. 17 



2 



Aug. 20 



3 



16 



81.23 



Do... 



...do.... 



4 



Aug. 13 



5 



Aug. 16 



3 



Aug. 19 



3 



Aug. 22 



3 



18 



81.68 



Aug. 5 ...do 



3 



Aug. 11 



3 



Aug. 15 



4 

 3.1 



Aug. 17 



2 



3.2 



Aug. 21 



4 



16 



81.29 



Average 



3.7 



3.5 



4.1 



17.7 



80.50 















SECOND BROOD OP ADULTS. 



Extent of reproduction. — Pairs of second-brood adults were con- 

 fined in arc-light globe cages to determine the number of winter eggs 

 deposited per female in the bark of apple. The data in Table XVII 

 were obtained in the fall of 1915, and that in Table XVIII in 1916. 

 The hoppers were allowed to remain on the trees until death. The 

 average number of eggs deposited per female during the two experi- 

 ments was 15.5 and 16, respectively. 



Attempt to rear a third orood of nymphs. — A globe-cage experiment 

 was conducted to determine whether second-brood adults would 

 produce a third brood of nymphs. Ten pairs were confined on August 

 7 in two cages and examined at intervals until October 1 . In no case 



