ArillDID.E OF FORMOSA. 105 



lu FormcTSa, all the iudividuals of this ajibis arc uraiigc vtllow iu their 

 general colour, the greeu oues having never been observed; and it is con- 

 tiunoiisly viviparous through jut the year, no sexes having Ijeen oljsorved. 



(Distribution") 



Formosa : Taihokn. 



Japan : Tokyo. 



Aphis sambuci L. 



(Host plants) 



Sctiidiucus racciitosK :Stunlurus thunhenji'ma : the young shoots and the 

 lower surface of the leaves are attacked. 

 (Season when the insect is aljundaut) 



Near Tokvii, this aphis is common from the ujiddle of April to the last 

 of June, the greatest abundance occuiriug alx)ut the liegiuuing of May. It is 

 very scarce iu the mouths of July, Augiist and Septemlier, during which 

 period very small colonies may be seen on the lower surface of the leaves. 

 (Winged viviparous female) 



Many winged forms occm', near Tokyo, in the second, third and fourlh 

 generatious fi'oiu the begiuuiug (_)f May onward t':» the list of Juui!. The first 

 :iud the fifth aud the following generatious consist usually only of wingless 

 forms, but the sexuparae are winged or wingless. 

 (Male and oviparijus female) 



Near Tokycj the sexes make their appearance h\>m the last of October 

 on. Tiie wingless oviparous fem.ales outnumlier the winged males, 

 (lutermediate) 



Many bra^^hypterous f jrms are cpiite commonly fouud among the sexuparae, 

 but they are very rare iu other generatious. 

 (Notes on the life hisfejry uear Tokyo) 



Tlie eggs liateh abjut the middle of March, the adults of the first genera- 

 tion i^stem-a other) occuiring from tlu middle of April on. Tlie females of tlie 

 •2ud generation reach their maturity from the hist of April tj the Ijeginuiug 

 ••)f May, when the greatest abuudauce takes place. Every male copulates with 

 several ovipai'ous females iu succession aud e;ich mating lasts for about seven 



