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11. Tramea limhata (Desj.),ybrmo. 

 \Lihellula limhata Desj., Rapport Soc. Maurice, i. (1832). 

 [Libellula mauriciana Ramb., Ins. Nevr., p. 34 (1842). 

 Tramea limhata Calvert, Proc. U. S. Nat. Mus., xviii. p. 121 (1895); Ent. Naclir., 

 xxii. p. 217 (1896). 



Tramea continentalis Selys, Mitth. Mus. Dresd., iii. p. 299 (1878) ; Martin, Mem. Soc. 

 Zool. France, ix. p. 102 (1896) ; Laidlaw, Trans. Linn. Soc. London, ser. 2, Zool., xii. p. 88 

 (1907). 



Tramea madagascariensis Kirby, Trans. Zool. Soc. London, xii. p. 317 (1889). 



Loc. Seychelles. Mahe : 4 ^, 3 $ (Dupont). Silhouette : Mare aux Cochons, 1 $, 

 1 ¥, IX. 1908. Praslin, 1905. Coetivy, 1905. Assumption Island: 3 ^, 1 ? (Dupont), 

 1910. Chagos Island, 1905. 



Dr Ris has very kindly given me a very full statement of his views, not yet published, 

 respecting Tramea limhata and the various geographical forms which it assumes. The 

 species was originally described from Mauritius, and under the single specific name Dr Ris 

 has gathered together numerous forms, usually regarded as distinct species, ranging from 

 Dakar in Senegal on the West, to New Caledonia and Samoa on the East. Restricting 

 ourselves to the area with which we are at present more directly concerned, it may be 

 said that, while the particular specimens to which the names continentalis Selys (from 

 Dakar) and madagascariensis Kirby (from Madagascar) were applied by their authors are 

 themselves sufficiently distinct from each other and from typical limhata, nevertheless, 

 specimens may be produced from both of these localities which closely resemble each other, 

 and to that extent differ from the typical forms of their respective habitats. For this 

 reason the use of the names continentalis and madagascariensis is attended with great 

 difficulty, and it seems to be preferable, for the present at all events, to designate as 

 T. limhata [forma] any specimen falling within the limits of variation of the species, but 

 not agreeing exactly with the typical form from Mauritius. 



Viewing as a whole the series obtained by the two Percy Sladen Trust Expeditions, 

 we see how variable the species is in respect of the size and form of the reddish-brown 

 basal spot on the hind wings. Thus, in the three males from Assumption Island (1910) 

 the basal spot is bounded externally by an almost straight line drawn downwards from the 

 cubito-anal cross-vein. Some of the Seychelles males are similar to these, but in others 

 the basal patch extends a little further outwards, while in two males from the Chagos 

 Archipelago (1905) the spot is very nearly as full as it is in typical limhata from 

 Mauritius. There is also variation in respect that the spot may either continue to the 

 hind margin of the wing or else curve inwards at some point before the margin is reached. 



In the females the spot is not less variable. In at least one of them (that from 

 Silhouette) it encloses a large hyaline space and is decidedly convex outside. It is 

 interesting to note how nearly some of the females approximate towards the specimen 

 from Madagascar which Mr W. F. Kirby presumed to be the female of his madagas- 

 cariensis. In addition to variability in this respect, one of the females, from Mah6, 

 has 8 antenodal cross-veins in each hind wing, instead of tlie normal number of 7. 

 SECOND SERIES— ZOOLOGY, VOL. XV. 56 



