GALL APHIDS OF THE ELM. 233 



Buckton, evidently with Riley's statement in mind but not 

 dearly, states, Vol. Ill, p. loo: — "Prof. Riley describes an elm 

 Aphis under the name of Schizoneura amcricana, and which he 

 thinks is distinct from Schizoneura iilmi of Europe. One pecu- 

 liarity of this insect is, that it rolls the leaves from below up- 

 wards, from which I gather that it feeds on the upper surfaces 

 instead of on the lower, as with us." Buckton describes the 

 leaf curl of ithni (p. 98) as "the leaf curl from above down- 

 wards into a roll of a sickly yellow colour." 



Kerner, Nat. Hist, of Plants, Vol. II, p. 533, figures uhni leaf 

 curl with the edge rolled under as with americana. 



The beautiful photograph of several leaves curled by tdmi 

 (which would portray leaf-curl of amcricana perfectly) in Brit- 

 ish Vegetable Galls by Edward T. Connold, 1902, is in accord 

 with his description of the gall of this species, which reads in 

 part (p. 246), "The affected half of the blade of the leaf curls 

 downwards and under, forming an uneven but gracefully shaped 

 roll." Pie states also : "Elm leaves may occasionally be found 

 where the blade has rolled upwards and along the upper surface. 

 They appear to be the work of the same species." This last 

 accords with Buckton (Vol. Ill, p. 103) : "I have occasionally 

 plucked leaves of the elm rolled from below upwards, but I 

 could not discover any unusual specific distinctions in the in- 

 sects inhabiting them." 



Schizoneiira fodicns Buckton, the currant root louse, has been 

 recorded as the underground form of Schizoneura tdmi* for 

 Europe and this point should prove suggestive for further ex- 

 perimental observations with Schizoneura amcricana. 

 *i896. N. Cholodkovsky. Zool. An::. No. 520, p^ges 508-513. 

 1897. N. Cholodkovsky. Zool. Ans. No. 530. 



1907. J. Barsacq. Le Jardin. Vol. XXL, No. 498, p. 348, Nov. 20. 

 1909. F. V. Theobald. Insect Pests of Priiit. pp. 221-222. 

 1909. Albert Tullgren. Aphidologische Studicn, p. 169. 

 Bibliography. 

 1879. ScJiiconeura americana Riley. Bui. U. S. Geol. and Gcograph. 

 Sui^vey. Vol. V, No. i, pp. 4-9 and Plate I. Fig. 2. Original 

 description and fullest account yet given. 

 1879. Scliizoncura amcricana, Thomas. (Ill) Report of the Stale En- 

 tomologist 111. VIII, p. 202. Quotes Riley's description of the 

 seven generations. Fig. 44 after Rile3^ Thomas concludes 

 (p. 204) : "This as admitted by Prof. Riley is very closely 

 allied to Schiaoneura ulmi Linn, and it is doubtful whether it 

 should be considered as distinct." 



