Spathegasfer haccanim. 15 



vegetation so that the bud gets little or no nutritive 

 material, gall formation cannot begin and the larva 

 perishes. Accordingly we find in a cold and late 

 Spring the galls of those flies which prick buds early 

 are very sparingly found. It happened, for example, 

 that the Spring of 1877 was cold and very late, and the 

 early galls were unusually scarce. This interfered 

 with experimental breeding and made my investigations 

 exceptionally difficult. If in every case where a bud had 

 been pricked by a gall-fly, a gall could be unfailingly 

 collected, then it would be easy to prove the succession 

 of the several generations ; unfortunately, however, 

 many of these experiments fail. 



In order if possible to guard against this, I had the 

 oaks which had been pricked brought into a warmer 

 room, so as to force them to shoot ; but even then 

 I was scarcely more successful. In some species cer- 

 tainly the development of the galls was hastened, but in 

 others on the contrary the results were negative only. 



[The Common Spangle is found on Ouercus pcdwiculata, Q. scssili- 

 Jlora, and Q. pubescens. 



Inquiline. Syuergus Tschtki in April. 



Parasites. Eurytoma signata, Toryntus atiraius, T. hibernans, 

 T. sodalis, Syntomaspis fastuosus, S. caudata, Pleurotropis rosarum, 

 in May. Ptcromahts dissectits, P. tibialis, Dccatoma bigiittata, Peso- 

 machus ga/iantm, Pleurotropis sosarnms, Entedon Jlavoniacidata, and 

 Megastignius dorsalis.'] 



P. Spathegaster baccarum\ L. 



Gall. Spherical, 3-5 mm. in diameter; of a greenish 

 colour, often studded with small red spots ; of soft, 



[^ Cytiips querctis-baccaritm, Lin. ; Spathegaster interruptor, Hartig ; 

 Neuroterus lenticularis^ sexual form, Cameron ; Neitroterus baccaruni, 

 Mayr.] 



