138 



THE OAK GALLS AND GALL INSECTS 

 (CYNIPIDiE) OF EPPING FOREST. 



PART II. DESCRIPTIVE AND FAUNISTIC. 



By E. J. LEWIS, F.L.S., F.E.S. 



{^Co7itimted from Volume XIL, page 286) 



IN studying the Oak Galls of the Forest, reference must be made 

 to the first part of this paper, which dealt with the struc- 

 ture and biological history of oak galls, with directions for 

 collecting and breeding. On the subject of classification, Mr» 

 Lewis observed, at the end of the former paper : — 



" Since the discovery by Dr. Adler of the alternating agamic and sexual genera- 

 tions among the oak gall-makers, the nomenclature has undergone a change. 

 The method adopted by ]Mr. Cameron is the truly scientitic one, but these 

 alternating generations present such variations that the generic names used by 

 Dr. Adler,! which serve to differentiate more clearly between the agamic and 

 sexual forms, are still adhered to in many cases." 



A List is, therefore, inserted here, showing the differences 

 between the nomenclature of these two authors ; and Mr. Lewis 

 added : — 



*' In the following account I have kept the generic name of the agamic 

 generation for the sexual generation also. In this respect I have followed 

 Cameron,2 but in the case of the specific names I have, with a few exceptions, 

 retained those used by Dr. Adler. 



" In the case of the three forms, Andricus fecundatrix, Andricus ?nalpighii\ 

 and Dryophanta divisa, I have found galls of the agamic generation only, and 

 have been unable to find specimens of the corresponding sexual generations, 

 Andricus pilostis, A. nudus and Dryophanta verrucosus respectively; so that in 

 this List these latter have been printed in italics. I have inserted them partly 

 because in giving an account of the generation cycle they must necessarily be 

 mentioned, and partly on account of the fact that as I have found the agamic 

 generation in Epping Forest, it is highly probable that the sexual generation is to 

 be found there also, and a description will, therefore, be of use in distinguishing" 

 these galls." 



The publication of this second part of Mr. Lewis' paper has 

 been delayed in the hope that figures of the galls might be in- 

 cluded. The author's engagements have prevented this, but it 

 is anticipated that figures may be given in a list of the oak galls 

 of Britain, with indications of their occurrence in Essex, which 

 is in contemplation. Meanwhile, we may point out that some of 



1 Alternating Generations. A Biological Study of the Oak Galls and Gall Flies. By 

 Hermann Alder, M.D., Schlesvvig. Translated and Edited by Charles R. Straton, F.R.C.S., 

 F.E.S. Oxford 1894. 



2 Peter Cameron's Monograph 0/ British Phytophagous Hymenoptera, \o\'. iv. Londoa 

 Ray Society, 18S2-92. 



