THE GENUS AURONYCTA AND ITS ALLIES. '6 



Stance that under several species I have written as though 

 aceris onh' presented this pecuharity, this is a lapsus requiring 

 correction. It differs, however, entirely, in the arrangement of 

 light and dark segments, and, since psi, tridens and strigosci, 

 which each have only one hair to a tubercle, resemble Viminia 

 in the alternation of light and dark segments, and are there- 

 fore nearer to them than kporina, I incline to regard this 

 duplication of anterior trapezoidal bristles as not indicating 

 close relationship. 



The eg^ of Icpovina (PI. VIII., fig. 3) differs from those of 

 all the other Acronyctas, to what at first sight appears a very 

 important degree, as regards its coloration. There is the outer 

 fringe of clear egg shell, but the inner egg is homogenous in 

 colour ; all the others, beginning with psi etc., which remain 

 clear, passing through megacephala, where the brown coloration 

 only reaches the length of separate dots, to alni, aceris etc., 

 where the dark colour is more abundant, have some pale areas 

 tending to be arranged in concentric circles of spots. In 

 leporina the pale area entirely disappears. The development 

 of the colouring is a very regular and beautiful process, the 

 egg, pale straw colour at first, as the inner egg shrinks away 

 from the shell, develops a chocolate dot at the vertex sur- 

 rounded by a small reddish circular patch, which is gradually 

 invaded by the chocolate colour, which is still, however, rather 

 bright or reddish ; then round the margin of the inner egg 

 appear 5 to 8 reddish spots, the inner chocolate area extends 

 angularly towards these spots leaving for a brief interval 

 between them a circle of pale blotches. Then the dark colour 

 absorbs the whole inner egg, which becomes of an uniform tint, 

 except that the ribbing of the shell, more markedly than in any 

 other species, gives in different lights some very pleasing effects 

 of a silky or pearly lustre. 



The egg exceeds one millimetre in diameter, is only about 

 •35 mm. in height, very variable in the number of ribs, two 

 specimens having respectively 41 and 63, the lesser numbers 

 are the more common ; towards the top they are waved into 

 arched lines enclosing distinct hollows, the white reflections 

 from the bottom of which, give the peculiar silky tone above 

 noted. The ribs increase by branching or separate origin, but 

 towards the margin are straight and simple. When first laid, 

 the egg is colourless. The micropyle presents the same rosette 

 of radiating willow-leaf cells as in the other species. 



The newly hatched larva (PI. VL, fig. 5) is 2 mm. long, white, 



