No. XXVIL— ODONATA. 



By Herbeet Campion. 



(Communicated by Prof. J. Stanley Gardiner, M.A., F.KS., F.L.S.) 



Read 16th January, 1913. 



The Dragonflies collected by the first (1905) Percy Sladen Trust Expedition to the 

 Indian Ocean, which I have had under review, were reported upon by Mr F. F. Laidlaw 

 (Trans. Linn. Soc. London, ser. "2, ZooL, xii. pp. 87 — 89, 1907), and his report included a 

 statement of the literature which he had consulted. 



The majority of the Odonata which form the subject of the present paper were 

 obtained by Mr Hugh Scott in the Seychelles Archipelago during eight months ending 

 in March, 1909. Simultaneously, Mr J. C F. Fryer, who accompanied Mr Scott to the 

 Indian Ocean, explored the island of Aldabra, and obtained Pantala Jlavescens Fabr., 

 Tramea basilaris Pal. de Beauv., Anax tristis Hag., Lestes ochraceus Selys {forma), and 

 Ischnura senegalensis Ramb. Mr H. P. Thomasset, in addition to taking an active part 

 in the collecting in Mah^, presented a pair of Lestes ochraceus [forma) taken by himself 

 in Cosmoledo in 1907. Finally, Mr R. P. Dupont, Curator of the Botanic Station in 

 Mah^, also assisted Mr Scott during his visit to that island, and moreover made a 

 collection in the island of Assumption in 1910, after the return of the Expedition to 

 England. His collection consists of the following species : — Diplacodes lefebvrei Ramb., 

 Philonomon luminans Karsch, Pantala Jlavescens Fabr., Rhyothemis semihyalina Desj., 

 Tramea basilaris Pal. de Beauv., and Tramea limhata Desj. [forma). 



Although no species new to science were discovered, there has to be recorded a new 

 and remarkable case of structural dimorphism attecting the ^ of Agriocnemis pygmaea 

 Selys (Synopsis). Beyond this, the female of Gynacantha stylata Martin has been found, 

 and other interesting additions have been made to our knowledge of the forms inhabiting 

 the islands. The occurrence of Philonomon luminans and of a representative of the 

 Subfamily Lestinae in those islands appears to be now recorded for the first time. 

 Apparently, the only Dragonfly previously published from Aldabra was the almost 

 cosmopolitan Pantala Jlavescens, and 1 believe that liitherto the Odouate-fauna of 

 Assumption and Cosmoledo has remained entirely unknown. 



I have much pleasure in acknowledging my indebtedness to two Continental experts, 

 for kind assistance rendered by them in the preparation of this report. Dr F. Ris, of 

 Rheinau, Switzerland, has obligingly given me the benefit of his unrivalled knowledge 



