ERIOPHYID.^ OR GALL-MITES. 



33 



Genus Monochetus. 



M. SULCATUS (Nal.) 



This genus contains a single species on beech, which is figured by 

 Connold.^ " These most interesting galls do not appear to be common : 

 they are very local where they 

 occur. The affected leaves are 

 situated on the new wood of 

 the year. They are attacked 

 while expanding, and instead 

 of opening out into a flat blade, 

 the primary offshoots from the 

 midrib are caused to remain as 

 nearly parallel as possible with 

 it, and the areas which they 

 enclose are pushed upwards, 

 giving both sides of the leaf 

 a deeply striated appearance. 

 They continue to grow in 

 length, and ultimately bend in- 

 wards, assuming a cymbiform 

 shape. The edges of some meet and produce a pod -like growth, 

 Owing to their excessive pilosity, they are like velvet to the 

 touch." 



Fig. Zb.— Edges of leaves 0} blackthorn (Primus 

 spinosa) rolled inwards by species o/Eriuphyes. 



Sub-Family PHYLLOCOPTIN^. 



In connection with this sub-family, it may be mentioned that 

 Nalepa gives several instances of Continental mites belonging to 

 the respective genera of the sub-family, and associated with many 

 of our forest trees. It is therefore possible that we have here, so far 

 as systematic forest entomology is concerned, a practically unworked 

 field. Fig. 36, a, represents the dorsal surface, and h the side view 

 of Phyllocoptes carpini IS'al.^ The figures are specially given as 

 showing the variety of structure in these minute creatures, and the 

 suggestiveness of this field for original microscopical research. 



The most familiar instance, however, is the species attacking the 



1 British Vegetable Galls, p. 176. 



- From ' Beitrage zur Sj^stematik der Phytopten,' von Dr Alfred Nalepa. 1889. 

 C 



