236 SOME SOUTH INDIAN INSECTS, ETC. [CHAP. Will. 



Cacopus systoma is prpbablj better known, bj sound at least. In 

 many districts in the Plains, notably around Madras, this frog is 

 common and its loud drumming note, so difficult of exact location, 

 is frequently hoard at night during heavy rain at the commence- 

 ment of the North-east Monsoon, although the extraordinarily 

 bloated frog itself is seldom seen and quite unfamiliar to most 

 people. The commonest Toad, both in the Plains and Hills, is 

 Bufo melanost ictus, which often enters bungalows in search of 

 insects attracted to the lights. 



The main food of frogs and toads is well known to be insects 

 and consequently these animals are always regarded as beneficial, 

 as no doubt they are as a class and on the whole. We have, 

 however, tew exact records of their food and feeding habits and it 

 is probable that these are so casual as to reduce their value very 

 largely. A frog which snaps up every insect which falls into a 

 pond, or a toad which will engulph any insect which moves, may- 

 do actual harm by destroying useful species, whilst many of the 

 real pests, being protected by nauseous odours or sharp spines, are 

 avoided ; a hungry toad, for example, will snap up a specimen of 

 Dysdercus cingulatus but immediately rejects it unharmed. Exact 

 records of the actual food of frogs and toads under natural condi- 

 tions in India are at present desiderata, whilst the field of inquiry 

 \s large and ready at hand to any observer. 



I i.. 109, Haplochilus lineatus, .< mosquito-eating fish. (After Day.) 



The main utility of Fish in India is as a source of food, but it 

 must not be overlooked that many fish, especially amongst the 

 smaller specie's, are of the utmost utility in reducing the number of 

 mosquitOS pit-sent as larvae in the ponds and other waters in which 

 such fish live, and this fact is often of the greatest importance in 

 determining the malarial factor in any locality. Several small 

 fish, especially the species of the genus Haplochilus, feed greedily 

 on mosquito-larva- and may easily be introduced into ponds and 

 wells in order to prevent mosquitOS from breeding in such places; 

 at Coimbatore we have also found that young individuals of 

 Macrones vittatus are extremely useful in this respect, but larger 

 individuals would probably require larger prey and do harm by 

 eating smaller fish. For it must be remembered, in stocking water 

 with small fish to reduce mosquitOS, that all large fish must be 



