BY T. H. JOHNSTON AND M. J. BANCROFT. 199 
at one time. The eggs are large in comparison with the 
size of the fly, measuring 1.5 mm. by 0.4mm. The female 
organs resemble those of WM. domestica but the maximum 
number of ovarioles observed in each ovary was 20 (fig. 30). 
The accessory glands are very long. The oviduct is a 
more muscular structure than chat of M. australis. There 
is a long ovipositor. 
The eggs are laid in a mass and placed below the surface 
of the dung. The egg shell is a thin, delicate structure 
covered with minute hexagonal markings. In warm weather 
the eggs hatch in less than 24 hours after deposition. The 
larva emerges as a first instar measuring 2 mm. by 
4mm. It grows rapidly and in a few hours moults. The 
second larval instar is marked by the appearance of the 
anterior spiracles each containing 6 to 8 processes. The 
posterior spiracles are now in the form of two almost straight 
slits (fig. 19). In 24 hours the larva measures 5.5 mm. 
by 1mm. It now moults for the second time, the anterior 
spiracles enlarge (fig. 15), likewise the posterior pair, which 
are now in the form of three sinuous slits surrounded by a 
black chitinous rim (fig. 17). During the next day the 
larva increases greatly in size, measuring 10 mm. by 1.5 
mm. No further appreciable growth takes place and by 
the fifth day the larva is mature and has entered upon 
the resting stage. The alimentary canal becomes emptied 
of food. The larva is now of a pale yellow tint and has 
become somewhat shorter and stouter, measuring 8.5 mm. 
by 2 mm. The puparium is yellowish brown to brown 
and measures 5 to 5.5 mm. by 2 mm. The pupal period 
occupies about 6 days in the summer and 10 to 14 days 
in the winter. The larvae pupate in the dung, but under 
laboratory conditions, at least, will leave it to do so. 
RELATIONSHIPS OF M. australis aNnD M. vetustissima. 
It appears that M. australis Macq., M. bezzii Patton 
and Cragg, and M. corvina Fabr., var. vivipara Portschinski 
are closely related flies. M. bezzii, a very common fly 
in certain parts of India, described and figured by Patton 
and Cragg (p. 352 and pl. xlv, fig. 2), is apparently very 
like M. australis in size and colouration. It is also a larvi- 
parous species depositing one larva at a time on cow dung. 
