CATALOGUE OF BRITISH PLANT-GALLS 251 
Sonchus arvensis Linn. 112. Corn Sow-thistle. 
Diptera Gregarious circular patches on the radical leaves ; green 
at first, becoming red or purple, glabrous or glossy. The 
swelling is the more pronounced on the superior surface. 
Each gall contains a white larva. M. G. Imago appear¬ 
ing in the autumn. (Plate XXXII.) 
CYSTIPHORA SONCHI F. Low 880 
Syn. Cecidoviyici scmchi Connold. 
Connold, Plant Galls, fig. 279. Houard, No. 6100. 
ERRATA 
The galls on Blackthorn leaves described on pp. 94 
and 197, and figured in Plate XXI., Fig. 1, are caused by 
Eriophyes padi Nalepa, not by Eriophyes similis Nalepa. 
The galls which result from the presence of Eriophyes 
similis on Blackthorn leaves are whitish, with an elon¬ 
gated hairy aperture (often with purplish margin) on the 
upper surface of the leaf. 
