APHIDID.E OF F0RM(1S\. 91 



(Wiuged vi\ip:a'ons female) 



The wiuged forms are veiy common in Formosa, as well as in Japan. 

 (Male and oviparoas female) 



In Formosa it Ls viviparous all the year, feeding eliietly on tlie aqnatii; 

 plants, and no sexes have been observed. 

 (Intermediate) 



No intermediates Lave been noticed. 

 ( DLstril:)utiijn i 

 Formosa : Taihoku, Kwannonzau. 



Rhopalosiphum pseudobrassicae (Davis i. 



(Host plants) 



Brassier, campeiiris : numerous females, both winged aud wingless, were 

 obseiTed on Ai^ril 18, 1922, near Taihoku. 



Bhaphanvs satlvps : Bramca olcraxm. 



(Japsella lvys:t-pc'stoi-i-^ : wiuged aud wiugless viviparous females were 

 observed on the leaves and stalks on Mai'ch 3, 1921, uear Taihoku. 



Chrij.santhemuiii coro/inrivjii : many wiuged and wiugless viviparous females 



were obsened on Jlarch 5, 1921, at Taihoku. 



Banv.ncvlus S'xIerait'S : niiiuy wiuged and wingless \iviparous femaks were 

 observed on February 27, 1921, at Sjzan, near Taihoku. 



This aphis is one of the most imp irtaut pests in our iskxnd, doing serious 

 damage t? the B/iop/ionm, etc. 



(Season when the insect is abimdautj 



Near Taihoku the gi'eatest abundance seems to occm- fi-om September to 

 April, its numbers lieing reduced during the surumer. 



(Winged viviparous female) 



The wiuged forms are commonly produced in Formosa, as in Japan. 



(Male and oviparous female) 



Tliis aphis is absays viviparous in Formosa, as well as neiu' Tokyo, and 

 no sexual forms have been observed. 



(Intermediate) 



No intermediates have lieeu noticed. 



