TWO LEAFHOPPERS INJURIOUS TO APPLE NURSERY STOCK. 11 



all overwintered adults had disap'peared ffom tlio trees by the first 

 weeik in July. 



Table I. — Longevity of overwintered adult apple leafhoppers; 50 adults placed in cage 



June 8, 1915. 



Date of examination. 



June 20. 

 June 21, 

 June 22, 



Do. 

 June 23. 

 June 24, 

 June 25. 

 June 20. 

 June 27. 



Do. 

 June 28. 

 June 29. 



Number 

 dead. 



Date of examination. 



June 30. 

 Do. 

 July 1.. 

 Julys.. 

 July 12 

 July 13 

 July 14, 

 July 15 

 July 16. 

 July 17, 

 July 18, 

 July 19, 



Number 

 dead. 



I Escaped. 

 Extent of Reproduction by Overwintered Females. 



Pairs of overwintered adults were placed on young trees in globe 

 cages to determine the number of eggs deposited by a female in con- 

 finement. The adult leafhoppers were allowed to remain on the 

 foliage untU they died. Examinations were made from time to time 

 and a record was kept of the number of nymphs removed at each 

 examination. This method of obtaining the extent of reproduction 

 does not take into consideration the number of eggs that failed to 

 hatch; however, it shows approximately the number of eggs deposited 

 by a single female. 



Two experiments were carried out and averages of 27 and 28 eggs 

 per female hatched in the respective cages. In Table II the number 

 of nymphs removed is given. 



Table II. — Number of first-brood nymphs produced by overwintered adult apple leaf- 

 hoppers in confinement, West Chester, Pa., 1915. 



Cage No. 1.— TWO PAIKS OF OVERWINTERED ADULTS PLACED IN CAGE ON YOUNG 



APPLE TREE JUNE 9, 1915. 



Dat« of examination. 



June 24 

 June 26 

 June 29 

 Julyl.. 



Number 

 of first- 

 brood 

 nymphs 

 removed. 



Date of examination. 



July?. 

 July 30 



Number 

 of first- 

 brood 

 nymphs 

 removed. 



Cage No. 2.- 



-THREE PAIRS OF OVERWINTERED ADULTS PLACED IN CAGE ON YOUNG 

 APPLE TREE JUNE 7, 1915. 



Jime24 

 June 2i.i 

 June 29 

 June 30 

 Julyl. 

 July 3. 



July7 



July 10 



July 20 , 



July 30 



Average 



28 



