200 Indian Museum Notes. [Vol, - 



Methods of attacking the eggs. 



It appears to me to be necessary for the fly to lay its egg* 

 attached to something which is washed by fresh water. It does net 

 appear very particular as to what that something is, whether, for 

 example it is a piece of weed or a brick wall, so long as it is station- 

 ary and will, so to speak, anchor the eggs. 



My opinion is that that anchorage must be destroyed. 



This can be effected by — 



(i) Cleaning the borders of the lake, and removing all the 

 weeds so as to leave clean earth banks. 



(2) Dredging away all weeds and low mud banks growing 



above the surface of the lake. 



(3) Scraping along the water line of all brick facings to the 



lake by means of such a scraper as seen in Figure IX,, 

 These scrapings would have to be placed in some metal 

 receptacle and finally emptied upon the earth, prefer- 

 ably into a fire. 



(4) The cleansing of stinking bays of the lake like that 



opposite the Government Store, Beira. 

 («>) The clearing of the Norris Canal and other such streams, 

 (6) The cementing of the little section of the Norris Canal 



just by the Principal Civil Medical Officer's Office. 



(The eggs were not found in the cemented portion, and 



it is my belief that these eggs originated by flies 



brought there by the Electric Tram.) 



I would also suggest two experiments. 



A. — That the Galle Face Lake bridge be scraped free of eggs 

 along the water line, and then tar be applied just above and below 

 that line, and the result watched. 



(The flies might not deposit the eggs on tar.) 



B. — That 50 yards of bank be cleaned and then faced with slag 

 from the engine waste mixed with tar, and the result watched. 



Estimated cost of cleaning the banks. 



I estimated the banks of the lake to be r 8,000 yards long, 

 I consider one cooly can cleanse 30 yards in one day. One cooly 

 costs 50 cents per diem. 



To cleanse the banks of the lake will require 600 coolies at 50 

 cents each, i.e., R300, i.e., £20 sterling. 



