266 PEECY SLADEN TEUST EXPEDITION. 



Our stay in Mauritius was far too short for any serious attack on its lepidopterous 

 fauna, which promises to be of great interest, although up to the present only the larger 

 and more conspicuous species have been collected, even the references to these being 

 scattered throughout the field of entomological literature. 



The three weeks which we spent in the Seychelles, followed by a further month spent 

 in Mabe and Praslin by Messrs. Stanley Gardiner and Porster Cooper after the departure 

 of H.M.S. Sealark, yielded a small but representative collection of the larger 

 Lepidoptera, our success being largely attributable to the ready and generous help of 

 the local collectors. Our thanks are due to Mr. J. A. de Gaye for kindly permitting 

 us to select a large number of insects (many of them unique) from his own collection, 

 and for forwarding specimens of several new and scarce species which he has discovered 

 since we left the islands ; to Mr. H. P. Thomasset, of Cascade Estate, for his liospitality 

 and most useful help in enabling us to collect along the higher parts of Mahe ; to 

 Mr. Dupont for a selection from a small collection of insects from the Seychelles and 

 from Marie Louise Island, Amirantes ; and to Mr. Connor for a small collection of 

 Lepidoptera irom Frigate Island. 



As regards the other islands, the collection may be considered on the whole as 

 satisfactory, and as probably representing some seventy or eighty per cent, of their Insect 

 Fauna. It must be remembered that the conditions under which we worked were not 

 of the most favourable. The short time at our disposal, the large amount of ground to 

 be covered, and the scanty number of workers, all combined to prevent exclusive 

 attention being devoted to any one group of insects. Our greatest amount of collecting 

 was done in the Chagos Group, but it was then the dry season (May-July) and perhaps 

 not the most favourable time of the year. To some of the other islands (South 

 Providence, Poivre, D'Arros, Eagle) we were only able to devote one day apiece, and 

 only two or three days each to Cargados Carajos, Farquhar, and Desroches. Under 

 these circumstances we could not expect to obtain more than a proportion of the 

 fauna of any particular locality, and probably of those obtained most belong to the 

 commoner and more conspicuous forms. 



One of the most interesting points connected with an insular fauna is the question 

 of the derivation and means of entrance of its component species. To attack this 

 question the first requisite is a knowledge of the range of the species outside of the 

 area under consideration, and I have therefore stated under each species its exact range 

 so far as it is known to me after a lengthy search through entomological literature and 

 collections. 



For ease in comparison of their distribution I have added a table of all the species 

 dealt with, showing their occurrence in certain areas around the Indian Ocean. 



Finally, I have endeavoured to analyze the geographical connections of the species 

 occurring in each of the main groups of the islands visited, and have added a few 

 suggestions as to the means by which they may have obtained an entrance into these 

 islands. 



The types of all species described as new in this paper, together with a selection of 

 the other specimens obtained, have been deposited in the National Collection. 



