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THE OAK GALLS AND GALL INSECTS
(CYNIPIDAE) OF EPPING FOREST.
PART II. DESCRIPTIVE AND FAUNISTIC.
By E. J. LEWIS, F.L.S., F.E.S.
(Continued from Volume XII., 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 scientific one, but these
alternating generations present such variations that the generic names used by
Dr. Adler,1 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 malpighii,
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 pilosus, A. nudus and Dryophania 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 tact 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., Schleswig. Translated and Edited by Charles R. Straton, F.R.C.S.,
F.E.S. Oxford 1894.
2 Peter Cameron's Monograph of British Phytophagous Hymenoptera, vol: iv. London.
Ray Society, 1882-92.