268 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XV, 



The larva dies rapidly if removed from the water and placed on a 

 dry surface, but will survive for several hours, possibly days, in a single 

 drop of water. I have seen it advocated that the destruction of 

 Anopheles can be extensively effected by dragging the tanks by means 

 of small skeined nets, and no doubt enormous numbers of the larvse 

 could be destroyed by systematically dragging the tanks and freeing 

 them from water weed ; but, if such a course be pursued, care should 

 be taken that the net be not again used until perfectly dry, as the larva? 

 will easily survive in the film of water clinging to the meshes of the 

 net, and will be simply replaced in the water. 



The larvse of Anopheles fuliginosus are killed in less than twenty- 

 four hours in a fifty per cent, solution of sea water and in a twenty -five 

 per cent, solution in a little longer time ; in a five per cent, solution 

 they will live for several days. The salt water acts as a direct irritant 

 to the breathing tubes, as the insects constantly try to clean them by 

 passing them through their mouths. 



[It is probable that, under natural conditions, some species of Anopheles are able 

 to bread in sheltered bays and inlets of the sea. I found A. rossii swarming in the 

 bungalows at Batticaloa where fresh water exists only in the deep wells used for the 

 supply of drinking water. There is no fresh surface water anywhere in the neigh- 

 bourhood. Some other Culicidce can make themselves at home in water having a 

 salinity of over 1 per cent. I particularly noticed an instance in which Armigereg 

 ventralis Walk., bred freely in a vessel of dilute sea-water containing 1 # 05 per cent. 

 of salt. The vessel was exposed in the verandah of my laboratory and was utilized 

 by the mosquitoes, although they had free choice of fresh water in the immediate 

 vicinity.— E. B. G.] 



In the case of a Culex larva placed in a saucer full of water, with 

 five drops of kerosine oil added, death took place in a quarter of an 

 hour ; the long straight breathing tube was evidently in difficulties ; 

 towards the end the larva swam about with its mouth out of water like a 

 fish in non-aerated water. Kerosine oil induces death from suffocation; 

 carbolic acid and izal apparently act as caustics. The larvae of Culex 

 were killed at once in carbolic lotion 1 in 40, but the pupse lived over 

 an hour ; izal destroyed both lame and pupse immediately. The 

 chitinous envelope of the pupse protected it seemingly from the action 

 of the carbolic acid for some considerable time. This strength carbolic 

 acid is evidently a very feeble insecticide. 



It is difficult to ascertain the exact length of time required for the 

 development of the insect from the egg to the imago, as hitherto I have 

 not discovered the egg of Anopheles fuliginosus. I have frequently 

 found the larvae when they have measured only 1 mm. in length, and 



