lU 



The Galls of Essex: a Contribution to a 



Fig. 40. Neurotcnis Iceviusculiis. 



This species, like its con- 

 geners, emerges fit'om the 

 gall in March or April. 

 Neuroterus l.i:viusculus, 

 Schenck (Fig. 40 1 [aga- 

 mous form of Spathe- 



GASTER ALBIPES.] 



QUERCUS EOBUR, L. 



Leaf. This small gall is 

 attached to the mid or 

 side ribs of the leaf on 

 its under side. It is egg- 

 shaped or oval, smooth, 

 hairless, yellow or brown- 

 ish, and often covered with 

 bright red or purplish 

 spots ; when matm'e it is 

 about one -tenth or one- 

 eighth of an inch in length. 

 The young gall is enclosed 

 in a thin membrane, which 

 splits lengthwise, and the 



scar on the leaf- vein is readily observable after the fall of 

 the mature gall in early autumn. It is single-celled, 

 with a relatively large cavity ; the gall-fly emerges there- 

 from in November or December. Neuroterus ostreus, 

 Hartig (Fig. 41) [agamous form of Spathegaster apri- 



LINUS] . 



Quercus Eobur, L. Leaf and male flowers. The common 

 "oak currant" gall is a smooth, sappy, green (fi-equently 

 more or less red on the catkin specimens), translucent, 

 spherical gall of about the size of a large pea ; it 

 occurs on the under side of the leaf (where it is con- 

 texturate with it above, exhibiting a well-defined, convex, 

 succulent swelling of the surface) and on the catkins, 

 generally four or five specimens on a single leaf or 

 catkin. It has a single larva-cell, which is small; the 

 gall grows very quickly, and the gall-fly emerges therefrom 



Fig. 41. Neuroterus ostreus. 



