1SS7.I 225 



slight approacli to the panoply of the 4th skin, whilst again in the 4th 

 skin some specimens approach the appearance of the 3rd ; so that 

 whilst the majority are abundantly distinct in these skins, in a few 

 it is impossible to decide to which skin they belong. 



From the 4th skin onward they are indistinguishable, althoi:gh in 

 the later skins the larvae are more certainly furnished with the lateral 

 tufts, and the dorsal tufts are more certainly of a uniform tint. But 

 a larva in its 4th skin may be as mature in these respects as one in its 

 6th skin. 



The first three skins, therefore, seem to be definite and fixed 

 forms ; the variability in moulting occurs in the later stages. When 

 we come to enquire into the significance of this variability, we meet at 

 once with one very decided fact, and that is, that those that moult 

 only three times always produce male moths, those that moult five 

 times always produce females, those that moult four times produce both. 



We may go on one step beyond this. The apterous females of 

 O. antiqua render in this instance more than usually marked the 

 circumstance that is usual amongst insects, that the female is much 

 larger than the male, from the fact that she contains a large number 

 of eggs. There is another circumstance that is also usually associated 

 with this fact, and that is, that the male emerges from the pupa a few 

 days before the female. 



Now, if we take the four-moulters, consisting of both males and 

 females, this is not so, the females emerge first, but if we associate 

 them in this order — 



fS-moulter males. r4-moulter males. 



i 4-moulter females. \ 5-moulter females. 



we find that the usual rule of the males emerging first is observed. 



This also shows more distinctly that another rule obtains in 

 O. antiqua. It is one that obtains among bees, and would, I think, be 

 found in other insects if observation on the point were made. It is 

 this, that the male, though feeding as larva a shorter time (being a 

 smaller insect), remains a longer time in the pupa state than the 

 female, apparently requiring a longer time to undergo its full 

 development. 



It would thus appear that in O. antiqua the female moults one 

 time more than the male, a cii'cumstance that I have not seen noticed 

 as occurring in any species, and that further the moults may vary 

 by one. 



I do not think my observations justify any conclusions as to the 

 circumstances governing this last point. 



