ENTOMOLOGY AT THE BRITISH ASSOCIATION. 307 



Among the numei'ous papers in the Zoological Section were several 

 devoted to one branch or another of Entomology. Professor Dixey 

 dealt with " The Geographical Relations of ]\Iimicry," pointing out 

 that certain definite schemes of colour and pattern in the wings of 

 butterflies are characteristic of certain definite geographical regions, or 

 even of sections of regions, and instancing his assertion by the well- 

 known combinations of red, black, and yellow Ithomiine, Heliconiine, 

 Danaine, Nymphaline and Pierine butterflies of Central and South 

 America, and by a similar parallelism between the local forms of the 

 African genera Mi/lot/iris and Phiissura. The extreme difficulty of 

 seeking an explanation of these facts in the common influence of geo- 

 graphical environment, made it more probable "in the views of many" 

 that these resemblances are due to the principle of mimicry of one 

 form or the other. But there are sure to be some anomalies to be 

 accounted for, and there maj^ even be mere coincidences due to 

 migration or chance. 



Mr. G. T. Bethune-Baker dealt with the question of " The 

 Correlation of Pattern and Structure in the linraliJac group of Butter- 

 flie?," and made an exhibition of butterflies of allied genera in the 

 Plebeiinae, Strtjmoninae, and Hinaliiiae, showing the changes in pattern, 

 colour and structure, and also changes of the same characters between 

 closely allied species in the genera Plcbeiin. and Iluralis. He also 

 showed a few species of the genus Arraea, in which the structure was 

 very similar while the colour and pattern were very diverse, and 

 others again in which the opposite was apparent. With slight 

 diversity of structure the difference would probably be only specific, 

 while if the structure were veiy diverse it would probably indicate 

 generic difference. But if this apparent want of correlation of colour, 

 pattern, and structure be studied with all available data, it will be 

 fouud that all genera which group themselves into sections like 

 Pa/iilio, Cliaraxcs, etc., as far as their colour and pattern are concerned, 

 are also grouped more or less distinctly in their structural details in 

 correlation to their pattern and colour. It would seem that colour 

 and pattern are more sensitive to mutability than structure. 



Dr. G. D. H. Carpenter discussed the " Enemies of Protected 

 Insects, with special reference to Acraea zetea." It was pointed out 

 that " protected " did not mean to imply protection from every enemy. 

 Such an immunity, would mean unlimited increase. Even the honey- 

 bee, well protected as it is, is preyed upon by the bee-eater, and hairy 

 caterpillars are consumed in quantities by cuckoos. The most 

 effective enemies of protected insects, however, are mainly predaceous 

 insects and parasites. 



Prof. E. A. Minchin, F.R.S., read a paper on " Sleeping Sick- 

 ness," a resiimt' of what was known of the cause of this terrible 

 scourge of Africa. It was pointed out that the disease was dependent 

 for its existence on two hosts in succession, a vertebrate (man, etc.), 

 and an invertebrate (the tsetse fly). The vertebrate host was not man 

 alone but largely antelopes as well as ruminants generally ; to the 

 latter hosts, however, the organism was innocuous. Various preventa- 

 tive measures had been suggested. If the flies could be wholly 

 destroyed, it was obvious that the disease would disappear. Some 

 would suggest the destruction of all game. Others would protect the 

 wild gallinaceous birds who would reduce the flies to a minimum 



