168 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



coming infested. So far I have not seen it on the white currants, 

 but it probably will attack them just as readily as it does the red. 



The effect on young stock is very disastrous, not only checking 

 growth, but in one instance, it was observed, killing the plants out- 

 right. A large number of year-old slips were found to have made 

 such poor growth at Swanley Horticultural College that they were 

 lifted, and all were found smothered with the aphis. Many of the 

 cuttings had scarcely grown at all, and the best had not made more 

 than a foot's growth during the summer. The effect on old-estab- 

 lished bushes is not so marked, but I have seen them die now and 

 again under the attack, and even when a few aphides only are present 

 on the roots the fruit runs off just before ripening. 



The aphides live in three ways below ground. The majority live 

 on the main stem, and there by the punctures of their proboscides 

 they cause the rind to split and peel off and the wood to crack. 

 Those that feed close to where the lateral roots come off cause large 

 rounded, swollen, gall-like growths. Others may be seen feeding on 

 the fine rootlets, and yet others in nest-like cavities in the soil. Buck- 

 ton found them from 4 to 6 inches underground. Those observed 

 this season have been found a foot or more down. 



The wingless forms appear to live in small colonies composed of 

 from ten to fifty individuals. These colonies probably represent the 

 progeny of one parent. As many as seventy colonies have been found 

 on one small bush. Those that live in earth cavities, through which 

 a small root runs, line the nests with a mass of dull grayish white 

 wool. Those that occur on the main roots do not produce so many 

 fibers, but, nevertheless, a sufficient number to give the plant a dis- 

 tinct mealy appearance, which sometimes assumes a dull, almost 

 gray, shade. The wingless females may be found on the roots all 

 the year round. 



During November many change to i3uija? and winged viviparous 

 females occur. Those wander about in the soil and many make their 

 way into the air and crawl onto the stems. After remaining there a 

 short time they fly off to other bushes, where they deposit young close 

 to the stem, often working their way into the soil. The production of 

 these winged females goes on into December. Buckton says (p. 95) : 

 " In October the larvse became very scarce, all the young passing into 

 pupse and winged insects." He also says that the wingless forms 

 were taken plentifully up to the middle of November. 



From what I have observed, the insects will go on breeding all the 

 year underground, every now and then in November and December 

 giving rise to winged forms. I have been unable to find out if these 

 winged females fly elsewhere than to neighboring currant bushes. 

 That they fly to the latter and there give rise to living young I have 

 found to be the case during the present season. 



Buckton figures -what he describes as " a vermiform young insect 



