J. Davidson 



55 



Series B. Infections from Rum ex to Different Plants, 



{a) Fundatrices of Afhis rumicis were transferred from Euonymus 

 to Rumex and the aphids reared. 



The following plants (to serve as stock plants) were then infected 

 from Rumex with winged migrants of the 3rd v. gen.: broad beans, 

 horse beans, poppies {Papaver rhoeas), peas, Rumex, and dwarf French 

 beans. From these stock plants three uninfested ones of each of the 

 above species were infected with one a. v. ?, 4th v. gen., and the number 

 of aphids produced in 14 days recorded. The following notes show the 

 progress of the infestation on the stock plants, and Table III gives the 

 number of aphids produced on the different plants. 



Broad beans. R. 25. 5. 14. Infected with 3 w. v. ?$. 7. 6. 14. 4th v. gen. are 

 all a. V. ??, some adult, large size. 22. 6. 14. Infestation heavy, aphids small size. 



Horse beans. R. '25. 5. 14. Infected with 3 w. v. ??. 2. 6. 14. The w. v. ?? 

 produced nothing, so reinfected with 2 w. v. ??. 11. 6. 14. 4th v. gen. in moderate 

 numbers, large size, all a. v. ??. 22. 6. 14. Infestation heavy, aphids small size. 



Peas. R. 2. 6. 14. Infected with 5 w. v. $?. 16. 6. 14. Moderate number of 

 4th v. gen., all a. v. ??. 15. 7. 14. Many aphids are restless, the plant fairly heavily 

 infested; many w. v. ?? present. 



Rumex. R. 24. 5. 14. Infected with 6 w. v. ??. 10. 6. 14. 4th v. gen. all a. v. ??. 



Papaver rhoeas. R. 28. 5. 14. Infected with 3 w. v. ??. 2. 6. 14. The w. v. ?? 

 produced nothing, so reinfected with 3 w. v. $?. 15. 6. 14. 4th v. gen. are a. v. $?; 

 not so large as on beans; some adult. 6. 7. 14. Plant heavily infested; many w. v. $? 

 present; aphids small size. 



Table III. 



Aphids produced 



Dwarf French beans not infected, reproduction poor. 



