114 i;V(»icm takahasiii- 



Frunus pcrsica : la.uiy m inj;o:l autl winyless vivi]jarou3 femules wore 

 oljseiTecl ou tlie lu'iver side nf the leiiveg ou April 9, ue;vr Tiiiliokn, on April 

 17, at Rhincliikii, and ou April 30, 1922, nt Tansni. 



Prunufi conimuids : many viviparous females, both vviuge.l and wingless, 

 wore olservod nn April 17, 1922, ut Sliincliikii. 



(Season when the inse^'t is abundant) 



On P/ii\igini(('>i <ommunifi it is usually found in small numbers at any 

 se:ison, but on Pruiim it occurs in large numlx^rs in April. 



(Winged viviparous female) 



Tlio winged forms are produced commonly from time to time. 



(Male and civi[arous female) 



It is viviparous througliont tlK> year, without the soxnales being produced. 



(luttirmediatj) 



!No intermediates have been noticed. 



(Distribution) 



Formosa : Taihoku, Tansni, Urai, Sliiuchiku, 



1>. Observations near Tokv'o. 



(Host plants) 



Phraijiuiks ajimaunis : the aphis is pr.'SL'nt on this pLmt from about June 

 ti the liist of November. 



Prunus jxrsiva : the viviparous females are found on this plant from May 

 t'j the last of Octoter. 



(Season wIkui the insect is abundant) 



This is one of tiie most common aphids near Tokyo. It occurs on 

 Pliraijm'dcs \n abundance fi'om the middle of June to the Urst week of July, 

 but is (juit*^ rare duriug th(^ summer. On Pnmm the g eatest abundance is 

 in June and July. 



(Winged vivii)ari>u3 fe.nale) 



Many winged forms appear in almost every viviparous gener.i^ion and the 

 sexupario are always provide<.l with wings. 



(Male and oviparous female) 



Tlie winged luales and sexnpara', which return to the winter host, Pnoais 

 pi, ska, are pnjdncsd alwut the middle of October on Phmg mites. 



T\\-o forms are found of those sexuparsc, the form maxinvx and the form 



