THE SECOND INTERNATIONAL CONGRESS OF ENTOMOLOGY. 271 



and white (hippocoon) form predominates, and the butterfly is 

 found to fly together with the black and white species of other 

 groups. At Durban three forms of the female {hippocoon, 

 trophonius, and cenia) occur, and all of them have been bred 

 from eggs laid by the same parent, together with a fourth form 

 [leighi), named after the discoverer, the late Mr. Leigh. 



Other papers upon evolution, bionomics, and mimicry, and 

 bearing on the subject of evolutionary processes as observed in 

 insects were contributed by the President, who gave an account 

 of Mr. C. A. Wiggin's and Dr. G. H. Carpenter's researches in 

 mimicry in the forest butterflies of Uganda; by the Rev. 

 K. St. A. Rogers ; and by Mr. R. G. L. Perkins, wlio .described 

 and compared the colour-groups of Hawaiian Odyneras (wasps) 

 found on the two neighbouring islands, Oahu and Kauai. In the 

 section of philosophic entomology Professor J. F. Van Bemmelen 

 (Netherlands) explained the phylogenetic significance of the 

 development of the butterfly wing, illustrating the development 

 of the colour pattern in the pupal and imaginal phases, and 

 showing how by the ancestral pattern, traced in this way, species 

 widely differing in appearance may be identified and classified 

 as members of the same family. 



Distribution. 



Several important papers were read on the subject of insect 

 distribution, and the assistance rendered to science, especially 

 to palaeontology, by a closer knowledge of the subject. Professor 

 Kolbe explained "Die Differenzierung der zoogeographischen 

 Eleraente der Kontinente," showing how the elements of the 

 existing insect fauna of Europe consist of circumpolar groups, 

 relics of ancient geological periods, and lately arrived groups 

 from Western and Central Asia and the tropics : the same 

 process being observable in North America, where, as in the 

 Old World also, over the southern continents are to be found 

 elements of the northern, of the tropical zone and of the antarctic 

 continents. Dr. Handlirsch dwelt on the relations between pale- 

 ontology, phylogeny, and " animal geography," and attempted 

 the solution of several interesting problems by statistical methods, 

 demonstrating thereby that many of the hypothetical " land 

 bridges " lately constructed between Africa, America, and 

 Australia will not stand scientific criticism on these lines. 

 While Dr. P. Speiser insisted on the importance of determining 

 how far their presence might be due to human agency in fixing 

 the antiquity of species in a given locality. 



Economic and Pathological. 



In none of the Sections was greater interest shown than in 

 the Economic and Pathological, where methods of combating 



Y 2 



