114 GEORGE O. SHINJI. 



5. The mustard aphis: 

 Aphis brassicce Linn. 



6. The Periwinkle aphis: 

 Myzus circumflexivum. 



7. The green pea aphis: 

 Macrosiphum nlmarice (Schv.). 



Aphis ulmarice Schr. 

 A. pisi Kalt. 

 Siphonophora pisi Koch. 

 6". ulmaricB Kalt. 

 Nectraophora pisi Oestl. 

 N. destructor Johns. 



8. The large rose aphis: 

 Macrosiphum roses Beaum. 



Aphis rosce Linn. 

 A. dipsaci Schr. 

 Siphonophora rosce Beaum. 

 Nectarophora rosce Linn. 



9. The large sonchus aphis: 

 Macrosiphum solanifolicz. 



10. The small sonchus aphis: 

 Aphis gossipii Glov. 

 Aphis citrulli Ashm. 

 A. cucumeris Forbes. 



X. SUMMARY. 



Results of the observations and experiments reported above 

 may briefly be summarized as follows: 



1. Either an apterous or an alate parthenogenetic female may 

 bear young larvae, some of which may finally attain the winged 

 condition, while the others may remain wingless throughout 

 life. 



2. When newly born aphids were reared on rose twigs planted 

 in tumblers, containing washed and sterilized sand which had 

 previously been saturated with the solution of a certain sub- 

 stance, nearly one hundred per cent, of winged individuals ap- 

 peared on the twigs, while either none or few winged forms devel- 

 oped on the twigs charged with any one of another set of chemi- 



