No. 3.] Calcutta Municipal Water. 195 



THE LAKE FLIES OF COLOMBO. 



Dr. Albert J. Chalmers's Report. 



The following report by Dr. Chalmers, forwarded to the Mayor by 

 Dr. Perry, P.C.M.O., has been printed and circulated:— 



1. Introductory, 



By the orders of Dr. Perry, the Principal Civil Medical Officer, 

 his investigation has been undertaken. 



I understand that Mr. Green, who is a most distinguished Ento- 

 mologist, has been asked by the Municipal Council to give a report. 



I therefore feel some diffidence in offering my report. 



I, however, thought that perhaps the Municipal Council desired 

 two quite separate and independent reports : one an expert report 

 from an Entomologist, and the other an ordinary report from a person 

 who is not an expert in such matters. Therefore in accordance to 

 orders received I beg to submit this short account. 



I would, however, beg that it might be considered merely in the 

 light as a very secondary report, and that its imperfections, which are 

 many, may be excused, as I have had very little time either to make 

 a study of entomology or to write this report. As few scientific 

 terms as possible are used in this report. 



I have to express my thanks to Dr. Perry, Principal Civil Medical 

 Officer, for his kindness in looking over my specimens and in giving 

 me certain very valuable assistance, especially with regard to the 

 methods to be adopted to diminish the numbers of these flies. 



I have also to express my gratitude to Drs. Griffin and Fernando 

 for many kind suggestions. 



I have to thank Mr. De Silva, the Assistant in Pathology in the 

 Ceylon Medical College, for several photographs taken from my 

 specimens. 



2. THE LIFE HISTORY OF THE LAKE FLY. 



The lake fly belongs to a family of the Diptera, or two-winged 

 insects, called Chironomidse ) and to the genus Chiro nonius, but I 

 have no means at my disposal to determine the species. 



The fly lays its eggs in jelly or mucous masses attached to water- 

 weeds and brick walls just at the water line. The eggs may be 

 found attached to almost anything which is stationary in the water. 

 I have not found any on the slag or waste from the Engine Yards- 



