Spathegaster vesicatrix. 21 



The flies are reared in exactly the same way as 

 Neuroferus leriticularis. 



Fly. 2-5 mm. in length ; black ; thorax dull, finely 

 punctate ; scutellum somewhat closely haired. The 

 colouring of the legs variable, yellowish brown, bases 

 of the femora mostly dark. Abdomen, looked at from 

 the side, almost round ; basal joints of the antennae 

 dark, which is the only character by which this fly is 

 distinguished from Neuroterus lenticidaris. 



Experimental breeding. Experiments, in the manner 

 described above, were also made with this fly, the first 

 being in March, 1875. From this first attempt, in which 

 thirty- two buds were pricked, I obtained in all five 

 galls which were formed under the leaf surface and 

 proved to be those of Spathegaster vesicatrix. In 1876, 

 I repeated the experiment with the same result. Later 

 also an English entomologist Fletcher ^ obtained from 

 similar experiments the same species of Spathegaster. 



[The silk button spangle galls appear in July on Qiierciis sessilijiora, 

 Q. pedmicidaia, and Q. pubescens. 



Inquiline. Syncrgns Tscheki, March to June. 



Parasites. Torymus tnutabtlis, June — August, T. inconstans, T. 

 fuscicrux, T. gcraniiin July. Platymesopus tibialis in June. Eiirytoina 

 ctirta,E. aethiops. Pteronialus dontesticusin. ]\Ay. Ettpebnusurozonus. 

 Pleurotropus sosarntusJ] 



3^ Spathegaster vesicatrix. Schltdl.^ 



Gall. These galls are inconspicuous and are em- 

 bedded in the substance of the leaf, which they resemble. 

 They project only slightly above the level of the surface. 



1 J. E. Fletcher, Entoni. Month. Mag., vol. xiv. p. 265 (May, 1878). 

 [^ Neuroterus numismatis, sexual form, Cameron. Neuroterus 

 vesicatrix, Mayr.] 



