ENTOMOLOGY NOTES 



BY 



E. C. COTES. 



I.— TRYCOLYGA BOMBYCIS, 



The Bengal Silk-worm Fly. 

 [Plate V,fig. 2.] 



A technical description of Trycolyga bombycis by the late Dr. 

 E. Becher is given on page 77. The economic 

 Sources of information, side of the subject has been dealt with in the 

 following papers : — 



1. A few notes on Sericulture in Bengal by J. A. H. Louis (1880). 

 %. Notes on the natural history of the Bengal silk- worm fly in the 



Rajshahye district by James Cleghorn, 1887 (published by 



the Government of Bengal). 



3. A letter by Nitya Gopal Mukerji, dated 7th October 1887 



(published by the Government of Bengal). 



4. Report of a meeting held in Berhampore on 12th November 



1887, by Nitya Gopal Mukerji (published by the Govern- 

 ment of Bengal). 



5. Aletter by C. W. Marshall, dated Berhampore, 20th July 1888 



(published in The Asian). 



In the present note, which is a summary of what has been ascertained, 

 much has been taken from Cleghorn's paper, which is a valuable record of a 

 very complete series of observations on the life history of the insect. 



The Bengal silk-worm fly causes considerable loss to silk-rearers in 



„ , , „,, . . Bengal, but somewhat contradictory statements 



Extent of the injury. , m 



have been made as to the extent of the evil. 



Marshall notices that the fly causes " enormous loss every year." 



Louis estimates this loss in Bengal at between £-200,000 and £300,000 



annually. Cleghorn notices a loss of five lakhs of rupees in a single 



crop, as indirectly due to fly. Mukerji recounts how the fly destroyed 90 



per cent, of a lot of silk-worms he attempted to rear in Berhampore, 



while his two village nurseries, which might have been expected to yield 



40 khaons each if_ the fly could have been kept off, produced only 8£ 



