TRANSACTIONS OF SECTION I). 475 



cause botli of the colour and of tlie luminosity. On July 17, at night, a fairly 

 large catch was almost wholly composed of Metridia bocchi. 



In the traverse across the Stnithern Ocean, between July 13 and 28, the 

 more noticeable forms in the plankton were Macrosetella, Fleuroiiuimma (twospp.), 

 Euchata (including one species probably new to science), Mecynocera, Corycceus, 

 Microsetella, C'alocalanus, Claiisocahunis, Sapphirina (S. metallina and S. 

 gemma), and the conspicuous black-coated Candacia aethiopica — along with 

 many diatoms and other smaller forms not yet identified. 



The volume of the plankton again increased on getting into the Australian 

 coastal waters. For example, on August 2, in Spencer Gulf, we had quite a 

 large catch of smaller Copepoda — chiefly Microsetella and Euterpinu. 



It is hoped that the detailed report upon these and the other oceanic 

 traverses will be laid before the Liverpool Biological Society in the course of 

 next winter. 



2. On Larvce o/ LinguUi (uul Pelagodiscus collected in the Red Sea and 

 Indian Ocean. By J. H. Ashworth, D.Sc.'^ 



3. Notes on Zoological ('(dlecling in Aufilralia with tlie British Associa- 

 tion in 1914. By Professor A. Dendy, F.R.S. 



4. Notes on Insects collected daring the Visit of the British Association 

 to Australia in 1914. By Professor E. B. Poclton, F.B.S. 



5. Bionomics of the Genus Eronia. By F. A. Dixey, F.R.S. 



Eronia is a genus of Old-World Pierine butterflies distributed over the 

 whole of Africa south of the Sahara, and southern Asia with the Malayan 

 islands as far as the Moluccas. It is remarkable for the diversity between the 

 sexes shown by most of the species, and for the fact that in nearly every 

 instance the females bear a strong resemblance to forms belonging to other 

 groups. The genus may be divided under subgeneric headings, as follows : 

 (1) Nepheronia, comprising the species inhabiting continental Asia and the 

 Malayan islands; (2) Leuceronla, consisting of four or five species wliich are 

 African and Arabian in distribution ; and (3) Eronia proper, which includes 

 two species belonging to continental Africa only. In Nepheronia the likeness 

 of the females is to various species of Danainae. In a few cases the females 

 of this section are dimorphic, each such form bearing the aspect of a separate 

 species of Danaine. In Leiiceronia three of the species have polymorphic 

 females ; these in every instance present a copy of some other butterfly belong- 

 ing to the Pierine sub-family but of no close affinity with Leuceronia. One 

 of the remaining species resembles in both sexes a Pierine of a distinct group. 

 The third section or sub-genus, Eronia proper, consists of two species, in both 

 of which the underside is coloured like a dead leaf. In addition to this, one of 

 the species is on the upper side almost exactly like another brilliantly coloured 

 Pierine inhabiting the same region. In this case the resemblance is closest in 

 the males. 



In the first group, the likeness to Danaines can scarcely be due to affinity ; 

 for, besides the fact that the males remain unaffected, there is no near relation- 

 ship between the sub-families concerned. Nor, in the second group, is the con- 

 nection close between the polymorphic females of Leuceronia and the Pierine.» 

 which they resemble. The "fact that the similar forms inhabit, speaking 

 generally, the same districts suggests a climatal or other local influence ; but, 

 besides the difficulty of conceiving the modus operandi of such an influence, 

 the polymorphism of many of the females and the unaltered aspect of the males 



1 See Trans. Roy. Soc. Edin., vol. li., pp. 45-69, Pis. iv., v., 1915. 



