Ii8 Records of the Indian Museum. [Vol. XVI, 



ot view into three categories: (i) surface forms, (2) mid-water 

 forms confined to still pools, and (3) bottom forms that can live in 

 rapid running water. The list of species collected in the stream- 

 lets at Khandalla is as follows ; I have distinguished the names of 

 those that belong to the first category with an *, those of the 

 species of the second category with a f and those of the species of 

 the third category with a §. 



Rhagovelia nigricans.* Heleocoris elongatus.^ 



Ptilomera laticaudata.* Naucoris sorclidus.% 



Metrocoris stdli.* Erithares templetoni.f 



Even in dealing with the Rhynchota T think it will be better 

 to defer a detailed discussion until it has been possible to investi- 

 gate the structure of Indian aquatic insects more completely. I 

 shall merely point out that the Hydrometridae of running water, 

 in India at any rate, usually differ from those that live on the 

 surface of pools and have either extremely long legs and bodies, 

 as in Cylindrostethus, or else have the body short and rounded 

 like that of the marine species, as in Metrocoris \ while the species 

 of Heleocoris are flattened and smooth and are thus well adapted 

 to cling tightly to stones or to make their way beneath and 

 between them. Such small, short-legged surface forms as Rhago- 

 velia live at the edge of the stiller parts of the streamlets and are 

 not perceptibly modified. 



III. The Fauna of Damp Rocks at the Edge of Water- 

 falls AT Khandalla. 



Where the small streamlets near Khandalla are precipitated 

 over the sheer basaltic cliffs that abound in the neighbourhood 

 waterfalls of different heights are formed. The larger of these, 

 where the water drops for some hundreds of feet, are practicall}'^ 

 inaccessible, but many smaller ones can be readily investigated in 

 which hundreds of feet are represented by tens and the amount 

 of water is by no means great. 



The fauna of these waterfalls is of considerable bionomic 

 interest, but what I have said in reference to insects of small 

 streams has even greater force here. The fauna of the actual falls 

 is perhaps exclusively entomological, its most conspicuous mem- 

 bers being certain moth-larvae that spin their flattened cocoons on 

 the rocks and certain caddis-worms that make bag-shaped reticu- 

 late snares of such strength that the water pours right through 

 without breaking them. At the edge of the falls, however, at 

 any rate in the dry season, a much larger and more varied fauna 

 has established itself where the rock is kept wet with spra}' and 

 the growth of algae is thus encouraged. 



Here again insects predominate, but other animals also occur. 



Batrachia. — Ixalus homhayensis is not uncommon in cracks 

 in the damp rock, and Rana limnocharis syhadrensis maybe found 

 under stones at the bottom of the falls. 



