120 Food Plants of Aphis rumicis 



In concluding this general introduction, it may be added that the 

 experiments, series B and C, have been carried out as far as possible 

 under natural conditions. 



The plants in the pots in series A, did not in some cases flourish 

 as well as might have been expected, owing to the dry summer. 



Experiments. Series A, B and C. 



The aphis species used in series A, B and C, is the Black Euonymus 

 Aphis (A. euonymi). All the aphids used in the first two series were 

 reared from a small colony found in January (27. 1. 1913) on a small 

 Euonymus bush in a garden near Richmond. In this way one was 

 quite certain that the same species of Aphis was being used throughout, 

 and further one knew exactly the history of the different generations 

 produced as the various plants were infected. 



The original colony on Euonymus was taken to the College green- 

 house, and the plant covered with a muslin bag. When winged forms 

 were produced, a clean Euonymus plant was infected. 



The experiments have been made in three series, A, B and C, and 

 have been carried out at Acton Lodge, Brentford, Middlesex, the experi- 

 ment orchard for the Department of Economic Entomology, Royal 

 College of Science, London. My sincere thanks are due to Professor 

 Maxwell-Lefroy for the kind and generous way in which he has given 

 me every facility for carrying on the work. 



The notes and observations given under the various dates will show 

 the results obtained. 



Experiments. Series A. 



The various plants indicated below, were infected with winged 

 viviparous females in every case, except in the case of Rumex, No. 2, 

 the aphides being transferred by means of a fine camel hair brush. 

 The plants were raised in pots from seed and kept covered with muslin 

 bags so that they were quite proof against external infection. During 

 rainy weather the plants were kept in a partly closed frame, but other- 

 wise they were kept in the open as much as possible. Observations 

 were made from time to time and notes made as given below. 



It will be seen in experiments, series A, that the chief food plants 

 of A. rumicis have been infected from different hosts ; thus, plants 

 Nos. 1, 2, and 3, were infected with aphids bred on Euomymus, plant B. 

 Similarly plants Nos. 4, 5 and 7 were infected with aphids bred on 

 plant No. 1, and so on. 



