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 finel}^ granular appear- 

 ance. In a former paper I erroneously stated that this membrane 

 or shell is smooth, or nearly so, Avhile still m 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"04mm. 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 <dgg 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 th-e 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 ^gg. 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 

 papillse 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 ra}'- vivarium in Melbourne hatched 

 out after an interval of a year and five months from the time of 



