ERIOPHYID^ OR GALL-MITES. 



29 



Eriophyes ltevis (Nal.) 



This species is found on the leaves of the common alder {Alnus 

 f/lutinosa). The galls are found on the upper surface of the leaves, and 

 are gregarious, often so abundant as to 

 cover almost the entire surface of the 

 leaf, generally glabrous, and very variable 

 in colour. Fig. 29. 



Eriophyes axillaris (Con.) 

 This species is also found on the leaves 

 of the common alder, but they differ from 

 the previous species, inasmuch as they 

 are always found on the midrib, or in 

 the axils of the primary veins from the midrib. The galls are 

 larger than the previous species, smootli, and varying in colour from 



Fig. "IS. — Galls on leaf of field 

 maple (Acer canipestre) caused by 

 Eriophyes maerorhynchus. 



Fig. 29. — Galls on leaves of common 

 cdder (Alnus glutinosa) caused 

 by Eriophyes Irevis. 



30. — Galls on midrib of the leaves of common 

 alder (Alnus glutinosa) caused by Eriophyes 

 axillaris. 



light-green to dark-brown, and always found in pairs. In section 

 they are hollow, and lined with hairs. Fig. 30. 



Eriophyes tetanothrix (kevis) (Nal.) 



This gall is found on the leaves of Salix caprea. This species of 

 willow is very common, and, as every botanist knows, very variable 

 as regards the size and shape of the leaf. The galls of this species 

 are generally found on the small-leaved variety, and on the upper 



