CATALOGUE OF BRITISH PLANT-GALLS 159 



larva. The greater part of the midrib is often involved, 

 the galls coalescent, and the leaf deformed. 



Perrisia carpini F. Low 211 



Syn. Cecidomyia carpini F. Low. 



Connold, Plant Galls, fig. 139. Houard, No. 1045. 



Acari Slight swelling in the angle between the midrib and a 



lateral vein. The depression on the under surface of the 

 leaf is covered with abnormal hairs. 



Eriophyes tenellus Schl. 212 

 Connold, Plant Galls, fig. 141. 



Leaf atrophied and wrinkled in a remarkable manner ; 

 the wrinkling extends from the margin to the midrib 

 along the lateral veins, which are slightly swollen below. 



Eriophyes macrotrichus Nal. 213 



Legnon confusum Bremi. 



Connold, Plant Galls, fig. 140. Houard, No. 1046. 



Fungi Dense mass of short twigs with atrophied leaves, 



usually seated upon a bough, forming the growth known 

 as a "witch's broom." 



Exoascus carpini Ros. 214 

 Connold, Plant Galls, fig. 137. 



FAGACEAE 



Oorylus Avellana Linn. 11 1. Hazel. 

 Diptera Staminate catkins swollen, more or less pyriform, with 

 enlarged, smooth scales. Larvae white, gregarious. 



Stictodiplosis corylina F. Low 215 

 Syn. Diplosis corylina F. Low. 

 Connold, Plant Galls, p. 245. 



Acari Masses of deformed twigs, forming a "witch's broom." 



The growth may be dense or straggling ; the leaves are 

 stunted, and the nodes are always swollen. 



Eriophyes avellanae Nal„ var. ? 216 

 Connold, Veg. Galls, pis. 14, 15. A very doubtful diag- 

 nosis. 



Staminate catkins swollen, more or less pyriform, 

 scales enlarged and rough. 



Eriophyes avellanae Nal. 



Connold, Plant Galls, fig. 134. Houard, No. 1053 (with- 

 out name). 



Bud deformed, hypertrophied, forming an almost 

 spherical yellowish or reddish-brown mass about 8 to 10 mm. 

 in diameter, composed of swollen scales, the innermost 



217 



