90 EYOICHI TAK.Vri.VSUI- 



Tliis species luay l)e soeu not luicoininniily, iie;ir Taikoku, :it iilmost tuiy 

 season, but it is not fi-eqiieutly \cv\ ubuudiiut 



(A\'in'j;eLl ^•ivip!U•oll^ female) 



Tlio wingetl forms are prodncccl fi'om time to time tli Jiiglioiit the 3'eir, luit 

 in very sm;ill niuiibor.s. 



(^[ali> Jiul oviparous female) 



It is vivi]):iroiis all the j'ear near Taihokii, where no koscs have been 

 f onnd oven in tlie wiuter. 



(Intormcdiati;) 



No iiitermediatos h;ne bwu noticed. 



(Distribution) 



lormosa: Taihoku, Kagi, Ivwaashiroi. 



Vesic iilaphis caricis (rull.) 



Host ])lant. -Cifpcrus rotvmhis. 



Numerous wingless viviparous females were collected b}' Mr. M. Maki on 

 January '25, and wingotl ones on Febniary 10, 1914. Tliis aphis seems to be 

 quite rare, since I liave never observed it during 1920 — 1922. 



Disti'ibution. — Formosa : 'I'aihoku. 



Rhopalosiphum nymphaeae (L.) 



(Host pLuits) 



Ndiuabo uuctfcni : the lower surfaces of the leaves and the stalks are 

 athickinl. 



Nymphacx sp. : the le;ives and stalks are attacked. 



Pislia stratiotes var. aniuUci : the leaves are attacked. 



Sa<jiU'iria sagiflfoUa : the lea\es and stalks are attacked. 



Near Taihoku the vivipiu'ous females inhabit those aquatic plants all the 

 year, without altomating the hosts, and ar(> rarely found on the Pntnvs communis. 



(Season when tha insect is abundant) 



Near Tailioku this aphis is vor\- common at almost any season, ot«asiou- 

 allv o.'cuiTin'r in lar>:e uumbei-s. 



