Galls caused by the larvae, nymphs, and imagines of 

 Monochetus sulcatus Nal. 



on 



the leaves of Fagas sylvatica Linn. 

 PLATE 72. 



Synonymy of Mite. 



Monaulax sulcatus Nal. 



Habitat of the Common Beech. — A large and tall tree of 

 majestic and noble proportions. Grows in woods and 

 forests in every part of England, where it is extensively 

 planted. 



Position of the Galled Leaves. — Mostly at the end of 

 a twig. 



Manner of Growth. — Villous ; cymbiform ; seldom more 

 than six affected leaves on one twig. 



Colour. — Green on upper surface, grey on under surface. 



Average Dimensions of a Mature Specimen. 



Length, 35 mm. ; breadth, lo mm. ; girth, 24 mm. 



May be sought during the months of June to October. 



The Growth is complete by the end of August. 



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 mid-rib 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 inwards, assuming a cymbiform shape. 

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

 Owing to the excessive pilosity they are like velvet to 

 the touch. 



The illustration is of specimens gathered at Hastings by the 

 author. 



176 



