196 wWUSCA AUSTRALIS MACQ., M. VETUSTISSIMA WALKER. 
length from 3.5 mm. upwards. The length given by Walker 
in his original account suggests that he was dealing with 
under-sized material. 
In the case of the female the wings, when at rest, 
overlap to a greater extent than they do in M. australis, 
whereas the position is alike in the males of both species. 
Male. 
Head. The eyes are very close, particularly in one 
region where they are separated only by the frontal stripe, 
the later being dark grey. Face and frontal region silvery 
but the latter does not extend dorsally beyond the point 
where the eyes approximate most closely ; it is therefore 
practically unrepresented in the region of the ocellar tubercle. 
Antenne brown with silvery tints. Arista (fig. 11) plu- 
mose somewhat as in M. domestica. Palps black. 
Thorax. The thorax is dark and shiny when lighted 
from the front. When the light falls on it posteriorly broad 
black bands can be seen. There are really four of these 
but the two of each side become more or less fused so that 
it is only in the prescutum that the four are usually recogni- 
sable. In the scutum there is a very broad band on each 
side especially anteriorly, while in the posterior part of 
scutum only the lateral band of either side is represented, 
These bands are joined together in the extreme anterior 
end of the prescutum. The central silver-grey band is 
variable in form. its sides being at times subparallel, while 
at other times they converge anteriorly so that the stripe 
resembles an elongate triangle. One then usually recognises 
the central silver-grey band, a lateral silver-grey band on 
either side and vestiges of silver-grey bands in the anterior 
part of the prescutum—one on either side. The scutellum 
has a darker patch in its anterior region and one at its 
extremity as well as a lateral pair (fig. 5). 
Wings (fig. 8). The wings are clear throughout. 
Each is relatively shorter than M. domestica. The nervure 
R 4+5 is-almost straight like that of W. australis. The 
first posterior cell is relatively shorter and the distal bent 
portion of nervure M 1-+2 is rather more bent than in 
M. domestica, while the angle approaches much more nearly 
to the hinder border of the wing. The median transverse 
