INSTITUTE, PUSA, FOR 1916-17 93 



separate cage as controls. Only in the control cage did the 

 flies begin to breed. No females without intercourse of 

 males were noticed to lay viable eggs; they laid eggs but 

 these were never seen to hatch out. Data regarding the life 

 duration from egg to egg, the longevity of a virgin fly, as 

 also of a fertilized mother-fly, etc., have been observed. 

 Under the same climatic conditions in captivity one female 

 will produce only males whilst another will produce females, 

 which seems to show that climatic conditions do not take 

 any part in the causation of sex. Perhaps age and food 

 have something to do regarding the causation of sex in this 

 insect. Experiments on this point would certainly repay 

 further study. 



Sarcophaga ruficollis. Members of the genus Sarco- 

 phaga are known carrion haunters. They extrude living 

 larvae instead of eggs and are amongst the first visitors to 

 exposed meat or dead animals. These flies are common 

 about human faeces, undigested cattle dung, and carrion. 

 They feed both upon sugary and nitrogenous substances. 

 They breed readily in flesh and human faeces. The larval 

 period as noticed is 10 days but the pupa takes double the 

 larval duration. Maggots which were extracted from a 

 tumour of a patient in Pusa Hospital proved to belong to a 

 species of Sarcophaga. 



Lucilia sp. A species of Lucilia, having a white face, 

 dark antennae and dark prothoracic stigmata, was seen 

 attracted to exposed meat and dead animals at almost all 

 seasons excepting during very severely cold days of winter. 

 The life-history from egg to egg occupies 25 days. One fly 

 was noticed to breed twice in her lifetime. The adults 

 were kept alive for a period of six to seven weeks. 



Lucilia sp. No. 2. This species differs from the above 

 in having golden yellow antennae. Freshly emerged female 

 flies when kept in a fly cage with males and all necessaries 

 of life refused to breed. Larvae pupate by instalments. 



Piophila casei (Sepsidae). These little flies visit meat 

 especially when the fatty tissues get advanced in fermenta- 



g 2 



