19*5 •] Fauna of the Chilka Lake : Aquatic Insects. 183 



Family Corixidae, 



Corixa substriata, Uhle, Distant, vol. V, p. 340. 



A single specimen, which apparently belongs to this species, was taken off Barkul 

 Point in March. The species occurs both in the plains and hills of India, in Ceylon 

 and also in Japan. 



Micronecta minihe, Distant, vol. V, p. 347, fig. 208. 



This species is common in the main area of the lake in the freshwater season and 

 also occurs in the same season near Manikpatna in the outer channel, where it was 

 found among vegetation submerged by the monsoon floods. M. minthe was originally 

 described from a number of localities in the plains of India and Ceylon. 



Micronecta proba, Distant, vol. V, p. 348, fig. 210. 



M . proba was common among water-weeds in Balugaon Bay in March. It was 

 described from the plains of Northern India and Upper Burma. 



NOTE ON THE GENUS EU RAT AS, Distant. 



The genus Euratas was described 03^ Distant (vol. V, p. 154) from specimens long 

 immersed in alcohol and then dried ; they were obtained in the Andaman Sea. From the 

 same collection and locality he also described (loc. cit., p. 155) a second supposed genus, 

 Fabatus, which, as he himself acknowledged, was based on immature specimens. An 

 examination of co-types of both genera and also of much fresh material has convinced 

 us that Fabatus is merely a nymphal stage of Euratas. The type specimens of the 

 latter , being mature, suffered comparatively little from the treatment they had received ; 

 but the much softer specimens assigned to Fabatus had shrivelled considerably and in 

 so doing had become distorted in such a way as to conceal their true generic characters. 



Mr. Distant has recently informed us in a letter that his chief reason for regard- 

 ing Fabatus as generically distinct was the emargination of the eyes, that is to say the 

 concavity of their posterior margin. In fresh specimens, however, that agree in all 

 other structural features with co- types of F. servus, no such concavity is apparent, but 

 in some specimens that have been preserved for even a few hours in alcohol, shrink- 

 age of the integument of the head and prothorax causes the eyes to protrude in the 

 manner shown in pi. xi, fig. 4. The emargination of these organs is therefore arti- 

 ficial. 



Euratas formidabilis, Distant. 



(Plate XI, figs. 1—7.) 



1910. Euratas formidabilis and Fabatus servus, Distant, vol. V, pp. 154, 155, text-figs. 82, 83. 



1911. Euratas formidabilis and Fabatus servus, Annandale, Reo. Ind. Mus. VI, pp. ni, 112. 



Distant's description of the adult of this species is excellent so far as it goes; but 

 unfortunately he makes no mention of the structure of the external genitalia, while, 

 owing perhaps to the position in which they are drawn, his figures of the anterior legs 

 do not fully illustrate their peculiar structure. As regards colour, his specimens in 

 this stage had suffered little and the only shrinkage apparent is in the prothorax in 

 which his figure exaggerates the discal foveations. 



