No. 3.3 Calcutta Municipal Water. 197 



present, to live in little mud cases which it makes out of any debris 

 which may exist in the vessel in which it is being- reared. 



The larvae now increase enormously in size, vide Figure VI. 

 which is a photograph of a larva in this red stage. 



Some days later the larvae become pupae. These pupae are of a 

 dark red colour, and breathe by means of white hair-like processes, 

 which are to be seen in the head-area. Figure VII is a photograph 

 of a pupa, but unfortunately does not show these white processes. 



Inside the pupae can be seen the insect more or less developed. 



The insect now ruptures the skin of the pupa and escapes. 



The empty pupal skins can be seen in the early evening floating 

 on the surface of the lake. 



Figure VIII shows a photograph of the male and female insects. 



The male has a long slender abdomen and the female a shorter 

 thicker one. The lowest figure is an insect in the act of escaping 

 from a pupa. 



During the day-time the adult insect appears to frequent shady 

 posts such as under bridges, the shade of the grass, weeds, shrubs, etc. 



At dusk, as is only too well-known, they fly about in the air. 



Figure IX shows the cage in which the eggs and larvae were 

 reared, the drawer being the portion which contains the water 

 with the larvae, eggs, and plants. The can attached to the stick was 

 used for collecting eggs and for obtaining larvae from the mud, etc. 



3. THE HAUNTS OF THE FLY. 



I have spent several hours investigating the haunts of the fly, and 

 find that it lays its eggs in jelly-like masses attached to the leaves or 

 stems of plants growing out of the waters of the lake just at the water 

 line. Also to tiie brick walls of bridges and to the brick facings ot 

 the banks of the lake just at the water line. 



If attention be now turned to the map of the lake, this will be 

 seen to be marked with red crosses, and these indicate where I have 

 been able to find the eggs of the fly. 

 A list of the places is as follows : — 



The banks of Rifle Green. 



The mud island close by. 



The margins of the Galle Face portion of the Lake. 



The bank of the Military Hospital. 



The Galle Face bridge (most marked). 



The Hunupitiya beach opposite the Public Hall. 



The stream by the Dhobie lines in Polwatta (most marked). 



