NOTES ON BIOLOGY OF SOME MUSCOID FLIES. — JOHNSTON. 97 



be abbreviated during the moister summer months (January 

 to March or April), but we have no records for that part of 

 the year. 



Awati (1920), in deahng with the biology of certain Indian 

 species of Musca, stated that M. promiscua (a species with 

 thoracic stripes somewhat like those of Al. vetustissima) passed 

 through its stages from the egg to the sexually mature imago 

 in 9 to 10 days (egg less than one day ; larva 1 ; pupa 4 ; 

 adult 4 days before maturity was reached), eggs being laid 

 from 4 to 10 days after copulation. The time elapsing between 

 egg deposition by a fly and by its progeny from such eggs 

 (i.e. from egg stage to egg stage) was found to be from 19 to 

 28 days. The longevity varied from 42 to 56 in the different 

 species of Musca under observation. 



Musca Jergusoni Johnston and Bancroft. 



This is much more robust than the last-mentioned species 

 and. has four well-defined thoracic stripes. It has received 

 several names. Macquart described it as M. australis, but the 

 name was already preoccupied by Boisduval. Hill (1921) 

 quoted these names as synonyms of M. licsoria Wied., an Indian 

 fly, the determination having been made by Bezzi. Johnston 

 and Bancroft transferred the species to VivijMromusca Town- 

 send (Johnston and Bancroft 1920c ; Johnston 1921b). 



Dr. Patton in a letter dated August 1921 stated that the 

 species belonged to the lusoria-bezzii group, but in a later note 

 (Dec. 1921) informed us that it was M. convexifrons Thomson 

 {7iec Bezzi). Its similarity to 31. bezzi Patton and Cragg was 

 pointed out in the original account (J. and B. 1920a). Until 

 the synonymy is definitely established we think it preferable 

 to use the above name. 



The various stages in the life-cycle and the periods of time 

 occupied have been dealt with (J. and B. 1920a ; Johnston 

 1921b). The fly is practically larviparous, as a larva in the 

 second instar escapes from the thin eggshell immediately the 

 egg is deposited by the female. Pupation occurs on the 3rd 

 day, the larval stages requiring 2 or a little over 2 days during 

 summer, but 4 in October and up to 6 in Avinter. The pupal 

 stage required from 9 to 15 days in summer and 27 to 32 days 

 in winter (Eidsvold). 



The fly has been found breeding throughout the year in 



