Galls caused by the queen and nymphs of Tetraneura 

 ulmi De Geer. 



on 



the leaves of Ulmus campestris Sm. 



PLATE 108. 



Synonymy of Insect. 



Aphis gallarum ulmi De Geer, Geoff., Von Gleichen. 

 Tetraneura ulmi Htg., Kalt, Koch., Pass., Buckton. 



Habitat of the Common Elm.— Widely spread throughout 

 Britain in parks, gardens, fields, and in hedgerows. 



The Gall is formed by the accumulation of sap caused by 

 punctures made in the leaf by the queen and nymphs. 



Position. — On the mid-rib and any part of the upper surface 

 of the leaf 



Manner of Growth. — Pedunculated ; solitary ; glabrous ; 

 perpendicular. 



Colour. — Pale green at base, darker in middle, suffused with 

 crimson at apex. 



Average Dimensions of a Mature Specimen. 

 Height, 12 mm.; breadth, 7 mm.; girth, 18 mm. 



May be sought during the months of June to October. 



The Growth is complete by the end of August. 



The Typical Condition of the gall is multinymphal. 



EcDYSIS takes place within the gall. The imagines emerge 

 during July and August. 



The gall is also figured by Buckton, " British Aphides," 

 vol. iii., plate 1 14 ; Kerner, " Nat. Hist, of Plants," vol. ii., p. 533. 



