J. Davidson 121 



Notes and Observations on Plants in Series A. 



Plant No. A. Eaonymus europaeus. 



Found infected with a small colony of A. rumicis, at Richmond, 27. 1. 13 and 

 transferred to College greenhouse. The colony developed, and about the middle 

 of February, many wmged viviparous females were produced. These swarmed 

 over the plant which became heavily infested. At the end of February, the aphids 

 swarmed over the plant in vast numbers. Many of them died off. The winged 

 forms crowded round the muslin bag, as though wanting to escape, and dissatisfied 

 with the plant. Many of the young shoots of the plant were killed, and the aphids 

 all died. The plant was kept covered till May 23rd, on which date there were no living 

 aphids present. It was then reinfected with Aphis euonymi, from some Euonymus 

 trees in Acton Lodge garden, and they produced several small colonies on the young 

 growuig shoots of this plant. 



It should be noted that owing to a hard frost occurring early in February, the 

 greenhouse was heated at night so as to make sure that the aphids would not die. 

 This doubtless hastened the production of winged forms. 



Plant No. B. Euonymus europaeus. 



This plant was infected from No. A, about the thud week in February, with 

 three winged viviparous females. They produced colonies of apterous females. 

 Winged viviparous females (2nd generation) appeared on this plant on April 27th. 

 By the 20th May, the aphids were very numerous on this plant, and both the apterous 

 and viviparous females were actively running over the plant, on the stakes supporting 

 the muslin bag covering it, and crowding over the muslin, as though wanting to escape. 

 By the end of the first week in June, many of the aphids were dying off. The aphids 

 were much smaller than the members of the original colony, this no doubt produced 

 by the fact that they were not feeding on the plant. Some specimens of the winged 

 forms, which I preserved at this stage, show that the abdomen is small and shrunken 

 in appearance. The apterous forms were also small, and present in extraordinary 

 numbers. Contrary to their usual sluggish habits, they were actively running over 

 the stakes supporting the muslin cover. 



On May 5th, I put one apterous viviparous female from B on a, clean branch 

 of a small Euonymus bush, and on another branch I put a winged viviparous female 

 from B. These both produced lice in 3 days, and although the numbers produced, 

 even after a month, were very few, yet the individuals looked fat and healthy. 



Plant No. 1. Rumex sanguineus. 



5. 5. 13. Infected from Euonymus B, with 4 w. viviparous $'s. 

 7. 5. 13. A few aphids produced. 

 22. 5. 13. Many colonies present ; collected round the apex of the young shoots, 

 also several colonies along the mid-rib of the leaves. Some of the 

 apterous forms are a smooth, shiny, jet black, colour, but many of 

 them are covered with a mealy bloom. 

 26. 5. 13. A few winged forms produced. 



