1^4 THE OAK GALLS AND GALL INSECTS 



backs of the tender leaves, causing tlie Neiiroterus fiimipennis galls 

 to make their appearance in August or at the end of July. 



OCCURRENCE IN EPPING FOREST. 

 Netiroterus fiimipennis was very abundant. I have occasionally 

 found this gall, together with Neuvoterus lenticularis, laeviusculus, 

 and 7mniisniatis, A udricus ostreus and Trigonaspis renum, all on the 

 back of the same leaf. First appearance noted July 29th* 

 Neuvoterus ivicolov was much less plentiful, and I only obtained a 

 few specimens. These galls when old often shed their hairs 

 and assume a brown dried-up appearance, exactly similar to an 

 old form of N. haccavum. The hairs, however, may remain on 

 the gall after it has dried up. I found this gall on May 30th. 



(5). V. Neuroterus schlechtendali (]\Iayr.) 



Gall. 



Appears on the catkin of the Oak in Alay forming a swelling 

 in the connective or upper part of the filament of the stamen on 

 each side of which are the anther lobes. This swelling is smooth^ 

 greenish-white in colour, with sometimes a tinge of pink, 

 becoming brown with age. The anther lobes are thrust up by the 

 swollen connective, forming what look like two flattened keels 

 extending on each side of the gall from just below the middle 

 to the apex. 



The galls appear in May, but the life history of the insect has 

 not been fully worked out, as the gall is uncommon ; the 

 perfect insects, however, emerge in July of the second year.* 



Imago. 



I have not succeeded in breeding any perfect insects from 

 these galls, 



This species is said by some authors to be the agamic form 

 of Neuroterus aprilinns, but the generation cycle has not yet been 

 fully determined. I have been unable to breed any flies from the 

 galls that I obtained in the spring, and if they appear in July it 

 seems probable that this may be a sexual, and not an agamic 

 form. 



OCCURRENCE IN EPPING FOREST. 



I found Neuroterus schlechtendali galls on two trees only, a 

 number of galls being present on each catkin. They appeared 



^AUernating Generations, Adler and Straton. 



