Cecidomyla ulmariae. 



The leaves on the opposite page are typical representatives 

 of the manner in which this species affects Spircea ubnaria. That 

 on the right-hand side shows the upper surface, the other leaf 

 the under surface : they bear galls upon them numbering 93 

 und 35 respectively. The largest number of galls the author 

 has seen on a leaf is 218. The mid-rib measured 7 in. long, 

 and had the same number of segments upon it as those in the 

 illustration. In some localities the galls are most abundant, 

 almost every leaf of each plant being attacked. The manner of 

 growth is most interesting. A tiny swelling shows itself on the 

 upper surface of a segment, pale green at first, then slightly 

 tinged with pink, turning later to red, at which period it is very 

 like an ovum of the puss-moth {Cerum vinula) in shape and 

 size, but with a depression in the centre. The surface, which 

 is glabrous under magnification in some specimens, shows 

 numerous minute reddish pimples. Meanwhile a cone-shaped 

 projection has been pushing its way through the under surface 

 of the segment, and continues until a length of 3 or 4 mm. 

 is reached. Some remain straight, but most recurvate some- 

 what. This portion is of a pale colour, and is thickly clothed 

 with long, greyish, silky hairs, more numerous at the base than at 

 the apex. Examples are not uncommon where the cones are 

 suffused with scarlet or reddish brown. The fewness or number 

 of them does not cause any discoloration of the segments, and 

 except they be extremely numerous there is no deformity of 

 growth. 



The illustration is of specimens gathered at Battle by the 

 author. 



