306 Scientific Proceedings^ Royal Duhlin Society. 



8. 5. 14. 2iid V. gen. are all a. v. ? 9 , large size, dull black in colour, with 

 parts of legs and antennae yellowish white in contrast ; the plant making- 

 young growth. 24. 5. 14. Plant heavily infested, aphids small size, many 

 w. V. $ ? present. 



Eitonynms A3. — 27. 4. 14. Infected with 2 a. v. 9 9 , 1st v. gen. from A. 

 18. 5. 14. Plant is not making young growth ; aphids small size ; majority 

 are w. v. ? ? , only 3 a. v. ? ? present. 



Huonymus A4. — 12. 5. 14. Infected with 5 a. v. 9 9 , 2nd v. gen. from A,. 

 24. 5. 14. 3rd v. gen. are a. v. 9 ? and w. v. 9 ? • 



Euonyvius A5. — 10. 5. 14. Infected with 3 a. v. $ 9 > 2nd v. gen. from A2. 

 24. 5. 14. 3rd v. gen. practically all w. v. 9 9 ; plant has young growth. 



Euonymus Ac- — 24. 5. 14. Infected with 4 w. v. 9 9 , 3rd v. gen. from A5. 

 10. 6. 14. 4th V. gen. small numbers but large size, all a. v. 9 9 , some adult. 



Euonymus A,. — 10. 6. 14. Infected with 8 a. v. 9 ? , 4th v. gen. from As. 

 20. 6. 14. Some aphids of 5th v. gen. are adult ; all are w. v. 9 ? ; plant has 

 young growth. 



Euonymus Ag. — 20. 6. 14. Infected with 6 w. v. 9 ? > 5th v. gen. from A,. 

 26. 6. 14. All the w. v. 9 9 have died without producing any young. Eein- 

 fected with 8 w. v. 9 9 from A,. 6. 7. 14. About 20 aphids 6th v. gen. 

 produced; killed off the winged mothers. 15.7.14. 6th v. gen. not yet 

 adult ; very small size ; plant not making young growth ; transferred the 

 aphids to a new plant. 23. 7. 14. Some of the aphids now adult ; all are a. v. 

 ? 9 small size ; plant is not making young growth. 30. 7. 14. Aphids very 

 small size ; plant woody ; several aphids of 7th v. gen. produced. 



Owing to the unavoidable termination of the "A" series in July, 1914, 

 the experiments were continued during the summer of 1920. As it was not 

 possible to find ova of Aphis rumicis, the experiments were staited with an 

 early apterous viviparous generation found on Euonymus europacics on 10th 

 May, 1920. Winged forms were present, so it might be presumed that these 

 were probably the second viviparous generation after Fundatrices. Allowing 

 ten days for development of each generation, this would mean that the eggs 

 hatched about April 10th. 



Small Euonymus trees grown in pots and covered with muslin bags were 

 infected as recorded below. By " cutting back " the bushes, young growth 

 was obtained throughout the summer. 



Euonymus Ei. — 10. 5. 20. Infected with two a. v. ? ? from Euonymus 

 europaeus. 15. 7. 20. Plant heavily infested. 



Euonymus Ej. — 15. 7. 20. Infected with 8 a. v. ? 2 from Euonymus Ei. 

 28. 7. 20. About 30 aphids produced, big and healthy ; plant has young 

 growth. 10. 8. 20. Many winged forms produced ; a few $ S present. 



