OF EPPING FOREST. 163 



white felt, or lump of cotton wool. The size depends upon the 

 number of galls collected together. 



Imago. 



Colour : Reddish yellow, shining. Antennae : Entirely yellow. Thorax : 

 IMesonotum finely punctured and dull. Abdomen : Darker on the dorsal 

 surface in the male than in the female, in the latter it is more or less brownish. 

 Levs : Uniformly vellow. 



Account of Generation Cycle. 



The insects emerge from the A. autunmalis galls in April, and 



•oviposit either in the flower or leaf buds, laying a number of eggs 



in each bud. According to Adler, flower buds are usually 



•selected because they mature earlier. About the middle of July 



the sexual generations appears from these galls, and the eggs 



are laid in the axillary buds. In October the A. antnmnalis galls 



appear; these mature at the end of the month, and fall to the 



/ground, the fly appearing in April of the second year, 



OCCURRENCE IN EPPING FOREST. 

 Andricus antnmnalis. Not very common. I was only able to 

 •find a few specimens of this gall. First appearance noted, 

 September 30th, 



Andvicns vaniuli. Not plentiful. These galls, as a rule, were 

 solitary, and appeared on the catkin more frequently than from 

 the leaf buds, but I occasionally found two or three matted 

 together into one formation. The thick felt-like covering 

 becomes reddish-brown with age. First appearance noted, 

 May 26th. 



(20.) Agamic Generation. X. Andricus ostreus (Htg.) 



Inquilines. Synevgns tscheki (Mayr) and S. tristis (Mayr). 



Gall. 



Appears from the veins on the underside of the leaf. It is 

 'Covered at the sides when young by two scale-like pieces which 

 give it the popular name of " the oyster gall." Colony : Yellowish, 

 .usually with reddish spots when young, sometimes entirely red, 

 yellowish brown when old. Shape : Usually oval, but sometimes 

 globular. 

 Imago. 



Colour: Brownish black, sometimes quite black. Antennae Dark, thickening 

 •towards the apex, paler at the base. Thorax : Keels on the median segment 

 very pronounced and curved. :May be streaked with dark rufous. Usually 

 slightly and finely pubescent. Abdomen : Shining. Legs : Reddish, becoming 

 -darker towards the base. IVinos ; Somewhat clouded. 



