BY ARTHUR DENDY. 
199 
is seen to have a thickness of about 0*036 mm. It is of a pale 
yellow colour when fresh, and has a very finely granular appear- 
ance. In a former paper I erroneously stated that this membrane 
or shell is smooth, or nearly so, while still in utero. It is true 
that the complete sculpture is not formed till the time of laying, 
but my recent observations have shown conclusively that the 
foundations of that sculpture are already present when the eggs 
are lying in the thin- walled part of the oviduct. These foundations 
consist of a number of little rounded protuberances regularly 
distributed over the surface of the thick membrane. They are 
not very obvious in fresh specimens and require careful looking 
for, but in specimens which have lain for a long time in alcohol 
previous to dissection the thick egg-membrane assumes a rather 
dark brown colour, and the protuberances may become conspicuous 
in surface view as much darker, well-defined circular areas about 
0-04 mm. in diameter. In addition to these protuberances the 
thick membrane frequently, perhaps always, exhibits longitudinal 
striations of an ill-defined character. (3) The fortunate discovery 
of an egg partially extruded from the greatly distended ovipositor 
in a specimen preserved in alcohol indicates the formation of a 
thin, transparent membrane outside the thick one just described. 
This membrane appears to be formed as a secretion, probably by 
the walls of the triangular sac at the base of the ovipositor. The 
abnormal conditions in the case under notice have prevented its 
even deposition, and the amber-coloured, chitinous (?) material is 
mostly collected in a large plug attached to what was the inner 
end of the egg. I have little doubt that the wrinkling of this 
chitinous (?) membrane as it dries upon the already embossed 
under-lying membrane gives rise to the complete sculpture of the 
perfect egg-shell, for the smooth papillae of the thick middle 
membrane exactly correspond in arrangement with the crumpled 
papillae of the perfect shell. 
The development of the embryo within the egg-shell appears to 
be a very lengthy business, for, as I have stated in a previous 
paper, one of the eggs laid in my vivarium in Melbourne hatched 
out after an interval of a year and five months from the time of 
