142 THE OAK GALLS AND GALL INSECTS 



(3.) Agamic Generation. III. Neuroterus numismatis 

 (01.). Inquiline, Symrgus tschehi (Mayr.) 



Gall. 



Appears on the back of the oak leaf, numbers being found on 

 one leaf. Commonly known as the "button gall." (Diameter 

 2 mm). Colouv : Brown. Shape : Round, resembling buttons 

 made of a light brownish silk with a more or less deep depression 

 in the centre. 



Imago. 



Colour : Black. Antennae : Brownish black, may be a little lighter in 

 colour at the base. Thotax : Dull. Mesonotum shining. Legs : Variable. 

 Usually brownish yellow in colour. Wings : Hyaline. 



(3.) Sexual Generation. Ilia. Neuroterus vesicatrix 



(Schltal). 



Gall. 



Appears imbedded in the leaf substance. (Diameter 2-3 



mm). Colouv : Greenish. Shape : Circular, slightly bulging the 



leaf surface. Centre somewhat raised, with rays running from it 



to the margin. 



Imago. 



Colour : Black. Antennae : Brownish 2-3 basal joints yellow. Thorax : 

 !Messonotum and scutellum smooth and shining. Parapsidal furrows usually 

 wanting. Legs : Yellow. Coxae and bases of femora dark. Wings : Hyaline. 

 End of ist cubital cellule slightly clouded. 



Account of Genevation Cycle. 



When the galls of A'', numismatis drop to the ground, 

 development continues in the dampness thus afforded. The 

 insects emerge from them about the end of March. The indivi- 

 duals of this, the agamic generation, proceed at once to oviposit 

 in the buds, the resulting gall, N. vesicatvix, appearing in the 

 leaf in May. From these galls the sexual generation of insects 

 appears in June, the eggs being laid on the under-surface of the 

 tender leaves. In three or four weeks the galls of N . numismatis 

 appear. 



OCCURRENCE IN EPPING FOREST. 



Neuvotevus numismatis was exceedingly plentiful, quite as much 

 so as N. lenticularis, the backs of the leaves often being entirely 

 covered. First appearance noted August 12th. Neuroterus 

 vesicatrix was not so common, the first specimen I met with 



