February, '15] 



GILLETTE: APHID FOOD PLANTS 



101 



months, the stems and flower heads often being hterally covered with 

 the lice. During September and October the males and the sexuparse 

 desert the Sonchus and go to species of Rihes, especially aureum and 

 vulgar e, where the sexual females are deposited, and, after fertiliza- 

 tion, deposit the over-winter eggs. 



This is undoubtedly the Rhopalosiphum ribis Koch, which Buckton 

 figured on Plate 39, Volume II, of his British Aphididse along with the 

 leaf galls of Myzus ribis. 



Rhopalosiphum hippophces Koch 



The summ.er form of this louse inhabits species of Persicaria exclu- 

 sively, so far as we have been able to determine. In the fall, the sexu- 

 parse migrate to species of Eloeagnus, Shepherdia and Hippophce, which 

 are closely allied plants, and deposit the sexual females which later 

 deposit their eggs about the buds. The males follow when the females 

 are about half grown. 



The over-winter hosts for this species also serve as winter hosts for 

 Phorodon galeopsidis Kalt., and Myzus hraggii Gill. As a paper by 

 the senior author of these notes, deahng with the synonomy of this 

 group, is expected to appear soon in ''Annals." We will not enter 

 into a discussion of the matter here. 



Rhopalosiphum pastinacce Linneus 



This species becomes very abundant upon Pastinaca and some 

 other Umbelliferous plants during the summer months in Colorado, and 

 in the fall goes to the honeysuckles belonging to the genera Lonicera 

 and Zylosteum. Both males and sexuparse migrate. 



Rhopalosiphum caprece Kaltenbach 



This species has been much confused with Pastinacce in the past 

 because it also goes to the UmbeUiferce as summer hosts, and in a general 

 way the two species are similar in appearance. Under the microscope, 

 however, caprece is easily distinguished by its caudal horn appearing 

 like a second tail, and its winter host is always a species of willow. 

 For a fuller discussion of these species see Journal of Economic 

 Entomology for 1911, page 320. These species could well be placed 

 in different genera. 



Hyalopterus arundinis Fabricius 



Occurs abundantly upon plum and prune as over-winter hosts, and 

 migrates in early summer to Reed Grass, Phragmites communis, from 

 which the males and sexuparae return to Prunus in the fall. 



Aphis bakeri Cowen 



This species winters freely upon both the cultivated apple and 

 Cratcegus. It migrates early in the summer to the white and red clovers. 



