Galls caused by the larvse of Hormomyia capreae Wtz. 



on 



the leaves of Salix Gaprea Linn, 



PLATE 95. 

 Synonymy of Insect. 



Cecidoiiiyia caprece Hardy. 



Hormomyia caprea; Hardy, Walker, Theobald. 

 Habitat of the Sallow, or Goat-willow. — Very 



common throughout Britain by the sides of streams, 



marshy places, damp open woods, and in thickets and 



hedges. 

 The Gall is formed by the parent insect depositing ova 



in the mid-rib as well as in other parts of the blade of 



the leaf. 

 Position.— On the under surface of the leaf, growing from the 



mid-rib. 

 Manner of Growth. — Singly, but usually a number coalesced ; 



glabrous. 

 Colour. — Pale green, pale yellow. 

 Average Dimensions of a Mature Specimen. 



Length, 7 mm.; breadth, S mm.; girth, 15 mm. 

 May be sought during the months of June to October. 

 The Growth is complete by the end of August. 

 The Typical Condition of the gall is plurilocular. Usual 



number of cells, 8. 

 The Larv^ pupate in the ground. The imagines emerge 



during the spring. 



These galls are amongst the very few kinds in which the 

 mid-rib itself is involved in their development. Looking at the 

 upper surface of the leaf it will be seen that the mid-rib is 

 broadened and much swollen by their growth. They project 

 from the under surface, forming conical swellings, which, when 

 mature, are very hard. When many are present on one leaf a 

 solid woody mass is formed, and the leaf is much distorted. 



The illustration is of specimens gathered at Hastings by the 

 author. 



