i88 Memoirs of the Indian Museum. [Voi,. V, 



Order LEPIDOPTERA. 

 Family Pyralidae. 



In thickets of Potamogeton off Barkul the larvae of a small moth, Nymphula 

 diminutalis, Snell, was abundant in the dry season , being able to endure a salinity 

 equivalent to a specific gravity of 1008. The same species breeds in brackish water 

 in the Gangetic delta, but is found also in many inland localities, having a wide dis- 

 tribution in the Oriental region and beyond. 



The caterpillar constructs its case, which closely resembles that of a Caddis-worm, 

 out of the narrow leaves of various water plants, arranging them parallel to one 

 another in a longitudinal direction. 



Mr. Meyrick has been kind enough to identify a moth of this species reared from 

 a caterpillar found feeding on Nais in brackish water at Port Canning. 



II. MARGINAL INSECTS. 



The insects to be considered under this heading include three species of Dermap- 

 tera, one Orthopteron and three Rhynchota. At least two species of Collembola 

 were also obtained in damp sand at the edge of the lake, but we are unable to ex- 

 press any opinion as to their identity. We may also refer to the curious Heterocerid 

 beetle (Heterocerus maindroni, Grouvelle) l which burrows in sand and sandy mud to 

 a point well below the water-level of the lake, taking to its wings at night and often 

 flying to the lamps of bungalows in the neighbourhood. It occurs at the margin in 

 places where the water is as salt as that of the Bay of Bengal near the lake, as well 

 as where it is fresh. 



The three earwigs are Labidura bengalensis, Dohrn, L. riparia (Pallas) and 

 Forcipula quadrispinosa, Dohrn. Of these the two former are doubtfully distinct. 

 All occur commonly under stones and particularly under alga that has dried on rocks ; 

 the Forcipula is a good swimmer, while Labidura can endure immersion in both fresh 

 and salt water. The species are also found in similar situations at the edges of 

 streams and ponds. L. riparia is a cosmopolitan species, while L. bengalensis , if it is 

 distinct, is widely distributed in India and Ceylon ; F. quadrispinosa is found also in 

 Burma and the neighbouring countries. 



The Orthopteron is a mole-cricket that agrees in every respect with the speci- 

 mens identified by the late Mr. Kirby as Curtilla (=Gryllotalpa) africana, Beauv. It is 

 nocturnal in its habits and usually burrows in mud at the edge of water. At Sat. 

 para it was found burrowing well below water-level in the salt-water season and its 

 song may be heard at all parts of the lake in the evening. Gryllotalpa africana is 

 the common species of the plains of India; its distribution is given as " Africa, Asia, 

 Australia, N. Zealand (introd. ?')"• 



1 Grouvelle, Ann. Soc. ent. France, L,XXII, p. 345, fig. (1903). 



2 Kirby, Syn. Cat. Orthopt., II, p. 6 (1906). 



