16 



BULLETIN 805, U. S. DEPARTMENT OF AGRICULTURE. 



placed in separate cages and a record of the number of eggs hatched 

 was kept. The average number of eggs deposited per female was 

 19.5 in. cage 1, 21 in cage 2, 20.2 in cage 3, and 18.4 in cage 4. 

 The total average for the four cages was 19.8 eggs per female. (See 

 Table X.) 



Table X. — Number of third-brood nymphs produced by second-brood adult apple leaf- 

 hoppers in confinem,ent. 



Cage No. 1— TWO PAIRS SECOND-BROOD ADULTS PLACED IN CAGE ON YOUNG APPLE 



TREE AUG. 5, 1915. 



Date of examination. 



Aug. 16 . 

 Aug. 23 . 

 Aug. 30. 



Number 

 of third- 

 brood 

 nymphs 



removed. 



Date of examination. 



Sept. 7 



Average per female . 



Number 

 of third- 

 brood 

 nymphs 

 removed. 



Cage No. 2.— THREE PAIRS SECOND-BROOD ADULTS PLACED IN CAGE ON YOUNG 

 APPLE TREE AUG. 5, 1915. 



Cage No. 3.- 



-FOUR PAIRS SECOND-BROOD ADULTS PLACED IN CAGE ON YOUNG APPLE 

 TREE AUG, 5, 1915. 



Aug. 16 . 

 Aug. 23 . 

 Aug. 31 . 

 Sept. 4. . 



Sept. 14. 



Sept. 28. 



Average per female. 



Cage No. 4.— FIVE PAIRS, SECOND-BROOD ADULTS PLACED IN CAGE ON YOUNG APPLE 



TREE AUG. 9, 1915. 



Third Generation. 



THIRD BROOD OF EGGS. 



Length of incubation period. — ^Three separate cages were used in 

 the experiments on the length of the incubation period of third- 

 brood eggs. The average incubation period was 9.6 to 10.3 days 

 for cage 1 ; 9.5 to 11.5 daj^s for cage 2; and 10 to 12 days for cage 3. 

 (See Table XI.) 



