OF EPPING FOREST. 



175 



The Cynips hoUari galls as a rule mature in September, the 

 flies emerging in October. Sometimes they emerge early in 

 September, while some remain in the galls during the winter, 

 appearing in April or May. 



The eggs are laid in the buds. 



According to Beyerinck, who carried on experiments with this 

 fly in 1 881, the first sign of gall formation occurs at the end of 

 May, maturity being reached in September, and oviposition 

 taking place in October. According to my own observations, 

 the galls are still very small at the beginning of July, dark 

 reddish brown in colour witli a prominent red apex ; by the 

 second week in July they had assumed a more globular appear- 

 ance and changed their purple colour for green, becoming golden 

 yellow before turning brown at the end of August. When 

 quite young I found in many instances that there were two galls 

 growing out from the axil of the leaf, one being of larger size 

 than the other as a rule, in which case the smaller dried up. In 

 other cases both galls continued to grow together. The 

 prominent apex of the young gall is represented on the mature 

 gall by a small point. 



When parasitised the galls are often smaller and much darker 

 in colour than the non-parasitised galls. The difference is some- 

 times very noticeable. In such cases, on making a section 

 through one of these galls it will often be noticed that towards 

 the centre there is a circle consisting of five or six cells of 

 Synergid larvae which have exterminated the cell of the original 

 maker of the gall together wdth its occupant. 



Over Europe the gall is widely distributed, but it is not 

 found very far north. It has been known in Britain for about 

 seventy years, and was probably introduced about 1830. It first 

 made its appearance in Devonshire, whence it has spread over 

 England and Scotland. I have found it abundant this year in 

 different parts of Kent, Devon, Monmouth, Brecon, and Cheshire. 

 In Epping Forest it is very common, but I have not found it 

 so abundant as in many other localities. First appearance noted, 

 June 30th. 



In conclusion, I may add that my researches have extended 

 over a small portion of Epping Forest only, namely, that part 



