J. Davidson 



129 



referred to in series A, were placed in the tent. These bushes had been 

 kept covered with muslin, and although the number of aphids produced 

 on the bushes by this date was very few, several healthy colonies were 

 present on them. The plants in the tent were carefully examined 

 before the infected bushes were introduced, and were found to be quite 

 free from aphids. They were very clean and healthy, and owing partly 

 to shade afforded by the muslin, and partly to the effect of the fumiga- 

 tion, they were making splendid growth. 



Owing to the colony of Aphids on the Euonymus bush placed in the 

 Compartment C not developing, no infestation of A. rumicis occurred 

 in this compartment, consequently no results were obtained. 



After the Euonymus bushes were placed in the tent, the plants were 

 kept under close observation and notes made from time to time. These 

 notes are given below, with the dates when the observations were made. 

 They show the results obtained, and indicate the progress of the infesta- 

 tion of the different plants by the winged migrants from the Euonymus 

 bushes. 



The following plan shows the arrangement of the food plants in the 

 different compartments. 



Door 



General plan indicating the general arrangement of the foorl plants in the tent. 



P. =Shii ley Poppies; 5. = Broad Beans; i?.B. = Red Beet; S.B. =Suga.r Beet; E.=:m- 

 fected Euonymus bush; ilf. = Mangolds ; <§.= Swedes; R. = Rumex sanguineus; 

 iV^. = Nasturtiums ; P.R.—Papaver rhoea ; 0«. =Onions. 



Compartment A. 



3. 6, 13. Euonymus bushes infected from Euonymus A, placed in the tent, 

 28. 6. 13. Some winged viviparous females have now migrated from the Euonymus 

 to Broad Beans, and a few colonies of lice are produced on these plants, 

 3. 7. 13. Aphids now infesting the Broad Beans in fair numbers, and many colonies 

 are present on the flower-stalks and tips of the young shoots. 



