INSTITUTE AND COLLEGE, PUSA, FOR 1912-13. 81 



Coloured plates were prepared illustrating all stages 

 of the life-history of the different species of Stegomyia 

 and allied genera occurring at Pusa, and a set of maps was 

 also constructed, largely from information received from 

 Medical Officers on the Stegomyia survey, showing the 

 known distribution of the different species in India. 

 These plates and maps, together with specimens of the 

 mosquitos in different stages and other exhibits, were sent 

 at the request of the Medical Department to the Inter- 

 national Exhibition at Ghent to form a part of the Indian 

 exhibit in the section of Tropical Medicine and Hygiene. 

 A typical collection of mosquitos and other human para- 

 sites was also sent to Dr. Marzinowsky of Moscow. 



A large number of observations have been made as to 

 the action of different chemical substances on the eggs and 

 larvae of mosquitos (Stegomyia scutellaris, Myzomyia 

 rossii, and Culex fatigans and microannulatus). 



It has been found that ordinary powdered Calomel 

 (mercurous chloride) has many of the properties of the 

 ideal larvicide, and this substance certainly merits a more 

 extended trial to ascertain its cost and efficacy under field- 

 jonditions. The action is comparatively slow, but "sure 

 and apparently lasting, while the amount which it is neces- 

 sary to use is so minute that treated water is in no way 

 harmful or uncomfortable for ordinary use by men or 

 cattle. 



Observations have also been made on the method of 

 feeding and the nature of the food and digestion of mos- 

 quito-larvae, and on the respiration and oxygen-consump- 

 tion of larvae and pupae. Methods of colouring mosquitos 

 for identification in flight- determination have been tried 

 with success as far as permanence and ease of identifica- 

 tion are concerned, both carmine powder and gentian- 

 violet giving good results. 



The breeding of West Indian " Millions," obtained in 

 the first instance from the Officiating Sanitary Commis- 

 sioner of the United Provinces, though quite successful 

 under " semi-domestic ' conditions, has been a failure when 



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