154 



FOREST ENTOMOLOGY. 



and yellow to red on one side. It is fairly common in some parts of 

 the country, but is more or less local (fig. 150). 



Dryophanta longiventris (Htg.) 



This gall (fig. 151) is somewhat like the previous species, and is also 

 found on the midrib of the leaves. It is brilliantly coloured with red 



and white stripes, and its rind may be 

 either smooth or slightly corrugated. It 

 is fairly common in some parts of North- 

 umberland. 



Dryophanta divisa (Adler). 



The galls are about the size of a small 

 pellet or buck-shot, and are found thickly 

 studded on the under side of the leaves, 

 springing from the veins (fig. 152). They 

 may be looked for from June to October, and 

 at first they are of a bright-red colour, but 

 they gradually change to a light-brown to- 

 wards maturity. The surface is smooth, with 

 a slight depression in the centre. The struct- 

 ure is hard and woody, with a comparatively 

 thick wall and small single larval chamber. 

 From a dozen to twenty may sometimes be found on one leaf. 



The flies hatch in October and November, and are about 4 to 5 mm. 



long. Antennae dark - brown ; 

 head and thorax brown ; ab- 

 domen black, and legs of a 

 lighter brown than body; wings 

 longer than body. 



Biorhiza Group. 



The first to be considered in 



this group is Biorhiza aptera 



(Fabr.) The galls of this 



of the oak, sometimes on the 



roots. The galls may 



Fig. 150. Gall of Dryophanta 

 Scutellaria (cherry gall). 



Fig. 151. Gulls of Dryophanta longiventris. 



species are found on the roots 

 smallest tips, at other times on 



strong 



