g [January, 



ProhaWy the fly makes the pocket to the rii^ht or the left as she sits at 

 work, but it is possible that she always works to one side, but sometimes 

 with head towards the base, at others to the end of the twig. 



The surface of the twig looks slatj^ grey, but on examining a pocket 

 containing an egii; is seen to consist of a very thin, delicate, superficial 

 bark of a brownish colour, no doubt dead bark-tissue, and beneath this 

 a bright green, no doubt living layer ; the brown overlying the green 

 produces the slaty tint. The egg-pocket is between these two layers, 

 immediately on the green layer and beneath the brown one. When 

 exposed by removing the delicate bark the egg is seen to be nearly 

 1 mm. long and about half a millimetre across, apparently nearly 

 circular in transverse section, the long axis parallel with that of the 

 twig, pale greenish in colour. It is supported and surrounded by a 

 green mass of adventitious tissue, either consolidated exudation or tissue 

 of the same nature as that of the galls, to the formation of which we 

 know the oak so freely lends itself. It would be interesting to know 

 whether this gall-like material forms the first meal of the larva, but my 

 cut twigs will probably not live long enough for me to ascertain this. 

 At first view this seems an unusual and, to me, quite a new feature 

 in the egg-laying of a sawfly, but it is obvious that it is parallel to, if 

 not absolutely identical with, the fluid exudation that occurs with the 

 eggs of sawflies laid in growing leaves and other tissues, that is at once 

 absorbed by the egg, which grows in some cases, before the embryo 

 matures, to a good many times its origuial bulk. 



Betiila, Reipate. 



November, 1918. 



ADDITIONS TO E. SAUNDERS'S CATALOGUE OF BRITISH 

 HYMENOPTERA (ACULEATA), 1902, AND CHANGES IN NOMENCLATURE. 



BY K. C. L. PEEKIJCS, M.A., D.SC, F.Z.S. 



Since the publication of the " Catalogue of British Hymenoptera 

 (Aculeata)" by Edward Saunders in 1902, a considerable number of 

 changes in nomenclature and some additional species have been brought 

 forward by various writers. From time to time I have noted these 

 down and they are here collected together. I have not in all cases been 

 able to verify the suggested changes myself, but have accepted the 

 opinions of others, who have greater facilities and probably greater 

 enthusiasm for making these investigations. 



