NOTES ON BIOLOGY OF SOME MUSCOID FLIES. — JOHNSTON. 99 



under similar conditions (egg less than 24 hours ; first instar 

 24 hours, second 24 to 48 hours, third 2 to 3 days, total larval 

 5 to 7 days ; pupal 7 to 10 days ; total from egg to emergence 

 12 to 17 — while the total in the case of the housefly during the 

 same month, November, was from 15 to 17 days). 



Additional data : — - 



Musca hilli Jnstn. and Bancroft. 



This is also a rather uncommon fly. Observations regarding 

 its biology have been made by Johnston and Bancroft (1920a, 

 p. 38 ; Johnston 1921b), working at Eidsvold and in Brisbane 

 during midsummer, the periods being found to be similar to 

 those of the housefly under similar conditions (larva 5 to 6 

 days ; pupa 6 to 9 ; total 11 to 15 days). In another paper 

 (J. and B. 1920b, p. 74) they refer to a total period of from 

 8 to 10 days from egg to emergence in Brisbane during mid- 

 summer. 



Observations show that the larval period in Brisbane during 

 midsummer ranges from 4 to 6 days (generally 5 or 6) ; the 

 pupal 5 to 8 (usually 6 days) ; and the total period between 

 egg deposition and emergence from 10 to 14 (usually 11 to 12) 

 days. 



Hill (1921) refers to this species as a synonym of M. nebulo 

 F., a common Indian fly, his information having been derived 

 from Prof. Bezzi. Major Patton in a letter (August 1921) to 

 the senior author stated that M. hilli was M. ventrosa Wied., 

 but in a later letter he reserved judgment. But Hill (1921) 

 recorded certain specimens from North Queensland as M. 

 ventrosa Wied. (syn. M. nigrithorax Stein) — Bezzi's deter- 

 minations, — but this refers to a different fly. We prefer to 

 retain the above name until the synonymy shall have been 

 settled. 



