68 
West_, on the Egg in Scatophaga. 
The species of Scatophaga revel upon excrement^ in which 
also they deposit their eggs_, which are of an oval form_, but 
have two broad divergent appendages at the upper end ; the 
object of which appears to be to prevent them from sinking 
in the matter in which they are deposited/^ 
The eggs (figs. 1^ 2^ PI. VII) are about a line in lengthy of a 
long elliptic form_, somewhat arched backwards^, the ventral 
surface being much the most convex. The top may be de- 
scribed as cut off obliquely from before backwards ; covering 
the opening thus formed is a lid or small door_, of a somewhat 
triangular shape^ which is articulated behind. A little 
beyond the centre of this lid^, on its under side, arises at 
tongue-shaped process^ by which the aperture is completely 
covered. From the upper fourth of the egg shelly where the 
cover is joined to it, arise with a gentle curve, and pass out 
obliquely on each side^ two arms or processes, about two 
thirds the length of the entire shell. The obliquity with 
which these pass off, as well as the amount of their curvature 
forward, vary in different examples, but in what may be con- 
sidered typical specimens the angle formed with the axis of 
the shell is about 45°. 
There can, I think, be no doubt as to the purpose served by 
these remarkable appendages, and that it is as suggested by 
the author above quoted. 
Investing the larva, and left behind after its exit, is a mem- 
brane, represented at m, in fig. 3. 
The egg-shell, which is of a horny texture, is covered with 
hexagonal reticulations, the interspaces minutely punctate 
with elevations (fig. 4). The processes are mere cuticular 
derivations, solid throughout, and finely elevato-punctate 
(fig. 5). That portion of the lid which covers the actual 
opening is of a rich, deep red-brown colour, and of a some- 
what different structure from that named above, being mapped 
with lozenge-shaped or 5-sided arese ; in the centre of each 
area is a rounded transparent spot, the space around very 
finely punctate (fig. 6). 
The eggs are deposited on the same material by different 
flies, and at different periods, so that larvae may be met with 
growing rapidly at the same time that others occur in the 
most rudimentary condition. Fig. 7 represents two broad 
toothed processes, from a larva gently pressed out of one of 
the cases ; the anterior pair of spiracles was distinctly seen in 
this individual ; but little else of structure could be traced in 
the granular mass of which it was composed. Larvae already 
hatched, and three lines in length, were obtained at the same 
time. 
