3°4 Records of the Indian Musetim. [Vol. XXIV, 



pods (Orchestia plalensis) which are found on islets of decaying 

 vegetation; and lastly Dipiacodes trivialis flies low over the 

 ground settling on waste places. This similarity of habits is a 

 further proof that the Odonate fauna is largely dependent on 

 immigration from the mainland. 



Anisoptera. 



Family UBELIvUEJDAE. 



Subfamily LIBELLULIN AE. 



Potamarcha obscura Karsch. 



Berl. ent. Zeitschr. XXXI II, p. 370 (1890); Ramb. (Ortlietrum, p. 

 38. n. 29) (Lib. obscum), Ins. Neu'r., p. 64(1842) ; Ramb., (Lib. con- 

 gene), loc. cit., p. 70 (1842); Kirby, Cat. Odon., pp. 38 and 180 

 (1890). 



Barkuda, 2 examples, 3-iiiia (Annandale, "caught in jun- 

 gle"); q-ig-ix-ig (Gravely). 



A comparatively rare species sometimes seen perched on the 

 ends of bare and prominent twigs in the jungle. 



Lathrecista asiatica asiatica Fabr. 



Lib. asiatica, Ent. Syst. Suppl., p. 283 (1798); Kirby (Orthetrum 

 asiaticum), Cat. Odon., p. 36 (1890) ; Ris, Cat. Coll. Selys (Lib.), 1908. 



Barkuda, 1 example, 6ix - io, (Annandale). 



This specimen, a female, was the only one taken on Barkuda. 



Brachydiplax sobrina Ramb. 



Lib. sobrina, Ins. Neiir., p. 114 (1842); Kirby, Cat. Odon., p. 17 (1890). 



A single male of this species has been taken, but the specimen 

 has unfortunately been lost. 



Dipiacodes trivialis Fabr. 



Ent. Syst. Suppl., p. 284 (1798); Ramb. (Lib. trivialis), Ins. Neur ; 

 p. 115 (1842); Uhl. (Lib. phalerata), Proc. Acad. Nat. Sci. Phil., 

 p. 30 (1858) ; Brauer (Diplax trivialis), Novara, p. 104 (18661. 

 Kirby (Trithemis trivialis), Cat. Odon., p. 18 (1890). 



Barkuda, many examples, 5 - viiri9 (Annandale ) "resting on 

 creeper on wall ") ; i2'viii"io, (Annandale, "in jungle") ; i^viii'io, 

 (Annandale, "flying low over bare ground, 10 a.m."); 25 , viii , io, 

 (Annandale, " common on the shore of the lake and also in waste 

 places"); 2y'\x-ig (Annandale, " from shore"); 3"x - io, (Annan- 

 dale, "caught in verandah of house"); a-iy'x'io, (Gravely); 

 24'x'io, (Annandale, "at light'*) 8 - iv*20 (Annandale and Dover, 

 " common on shore") ; n-iS'xii'ig (Annandale). 



This is one of the commonest dragonflies on the island at 

 all seasons. It generally flies low over the ground, settling in 

 waste places, and probably for this reason is most abundant on 

 the shores of the island. Dr. Annandale tells us that it often 

 falls a prey to spiders that build their webs on the ground. 



