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No. XI.— LEPIDOPTERA, EXCLUSIVE OP THE TORTRICID^ AND TINEID^, 

 WITH SOME REMARKS ON THEIR DISTRIBUTION AND MEANS 

 OF DISPERSAL AMONGST THE ISLANDS OE THE INDIAN OCEAN. 



By T. Bainbrigge Eletcher, B.N., F.E.S. 



{Communicated by J. Stanley Gardiner, M.A., F.R.S., F.L.S.) 



(Plate 17.) 



Read 17th June, 1909. 



Table of Contents. 



Page 

 I. Introduction 265 



II. Systematic List 267 



III. Synopsis of the Distribution - Table, showing Geographical Affinities of Lepidoptera 



in each Group of Islands 313 



IV. Table showing the Distribution of the Lepidoptera in and around the Indian Ocean .... 314 



V. On the Distribution of the Lepidoptera in the Islands of the Indian Ocean 317 



VI. On the Means of Dispersal of Lepidoptera in the Islands of the Indian Ocean 319 



VII. On Widely Distributed Forms of Lepidoptera 321 



VIII. Literature 322 



I. Introduction. 



The present collection, consisting of about 1218 specimens of 131 species *, was 

 made during the Percy Sladen Trust Expedition to the Indian Ocean in H.M.S. 

 Sealark, during the months of May-November 1905. A general account of the 

 Cruise, with a description of the islands visited, has already appeared in these 

 ' Transactions ' (vol. xii. parts 1 and 2). 



Omitting consideration of Mauritius and the Seychelles, the geological character of 

 all these islands may roughly be stated to be coralline and their soil calcareous. They 

 are all low-lying, being scarcely elevated above the level of the sea, and the similarity 

 of their soil limits to a large extent any great diversity in the vegetation, the uniformity 

 of this latter of course governing the insects. Hence we can hardly be surprised to 

 find a remarkable paucity, not merely in the variety of species in these islands, but 

 frequently also in the number of their individuals. 



* Exclusive of the Tortricidse and Tineidse, which Mr. E. Meyrick, F.R.S., has kindly undertaken to determine. 



