54 



Biological Studies of Aj^his rumicis 



Rumex. A. 22. 5. 14. Infected with 3 w. v. ??, 3rd v. gen. from Euonymus. 

 8. 6. 14. 4th V. gen. are all a. v. $?; 17. 6. 14. w. v. $? present, infestation heavy. 



Dwarf French beans. A. 22. 5. 14. Infected with 3 w. v. ??. 8. 6. 14. Only 

 4 aphids alive, the w. v. ? mothers dead. 18. G. 14. All the aphids produced on this 

 plant are dead. 



Table I. 



(b) Three plants of mangolds, red beet and sugar beet were in- 

 fected, each, with one w. v. ?, 5th gen. from Euonymus, and one a. v. ?, 

 6th V. gen. was left to reproduce on each plant. The number of aphids 

 on each plant after 14 days are given in Table II. 



Table II. 



Aphids produced 



