Watt. — Ova of some of the Lepidoptera of New Zealand. 71 



Dimensions. — Height, 044 mm. ; diameter, 0-61-0-65 mm. 



Sculpture. — Similar to that of M. insignis. Exceptions : Total number 

 of ribs, 33-40 ; dimensions of cells at equator — length 0-05 mm., width 

 0-02 mm. The length of the cells is taken at right angles to the longi- 

 tudinal ribs. 



Micropyle. — A small deep circular cell situated in the centre of a rosette 

 of eleven elongated cells. The rosette is slightly elevated, and is surrounded 

 by a band of about twenty elongated cells, about twice as long as broad, 

 lengthened in direction radial from the micropyle, dimensions being — 

 length about 0-05 mm., width about 0-03 mm. There is a second band of 

 irregular pentagonal and hexagonal cells from which the main ribs originate. 

 Diameter of micropyle, 0-01 mm. ; rosette, 0-08 mm. 



Shell. — Transparent ; fairly strong ; shiny ; slightly roughened within 

 reticulations. 



Colour. — When fresh laid, creamy white, changing in about four days 

 to a light-brown mottling on upper half of egg. On the fifth day the upper 

 surface of the egg (above the equator) is light brown with small creamy- 

 white areas surrounding the micropyle. Below the equator the colour 

 remains pearly white till near the date of hatching. In seven days the 

 colour is a dark blackish-grey, a slight mottling still apparent. Just before 

 hatching the colour gets much lighter in shade, and the creamy area below 

 the equator turns a very light grey. The hairs of the larva are very plain 

 at this stage, and the reticulations become white and very plain. Infertile 

 eggs collapse without undergoing changes in colour. 



Note. — These eggs are laid in batches in neat regular rows ; sometimes 

 there are two, and even three, tiers of eggs in one batch. Well attached 

 to food plant, and slightly to each other. Batches obtained in April and 

 October to December, consisting of from 180 to 92 eggs. Period of in- 

 cubation fourteen to eleven days, according to weather. The parent moth 

 does not always confine herself to laying only one batch, sometimes laying 

 two, or even three, or more. When the eggs are first laid they are very 

 soft, and are often pressed into irregular shapes by their neighbours, but this 

 does not seem to affect them in any way. The larvae emerge through the 

 top of the egg to one side of the micropyle, and make their first meal off 

 the empty shell. I have found hundreds of batches of these eggs on the 

 underside of the leaves of the white magnolia, and several batches on the 

 underside of the leaves and on the bark of the red flowering gum. The 

 moth also often lays her eggs on windows and walls of houses and other 

 seemingly most unsuitable places. 



(Described, 17th April, 1912.) 



I add here descriptions of eggs belonging to two varieties of this moth 

 (Melanchra matans) which are very common. These differ quite enough 

 to make one believe at first sight that they belong to different species. 



VARIETY A. 



Ovum. 



The main differences in this egg are as follows : — 



Dimensions. — Height, 0-37 mm. ; diameter, 0-65 mm. 



Sculpture.- — Total number of ribs. 43-45 ; cells about 0-02 mm. square. 

 Ribs 0-02-0-03 mm. apart at equator. The cells here do not show the 

 modified hexagon form. 



