41 



Notes on the Earlier Stages of Nola albulalis. 



By Robert Adkin, F.E.S. Read November nth, 1909. 



During each of the past three summers I have obtained a few ova 

 of JVola albulalis from East Sussex parents, and although from the 

 point of view of rearing imagines from them I have not been par- 

 ticularly successful, I have at least been able to get the larva through 

 all its stages, and to have the satisfaction of seeing the moth emerge, 

 but out of its due season. All attempts to hibernate the larva have 

 failed, but this last autumn some half-dozen larvae, yielding to a 

 warm temperature and an abundant food supply, very obligingly fed 

 up, pupated, and produced moths early in November, thus enabling 

 me to follow the life-history of the species, even if under somewhat 

 artificial conditions. 



On all three occasions the eggs have been laid in confinement, but 

 as they have invariably been deposited in exactly similar positions, I 

 take it that we shall be right in assuming such positions to be the 

 natural ones. They are on the back of the leaf of the dewberry 

 iyRubus ciEsius), and either at the junction of a vein with the mid-rib, 

 by the side of the mid-rib, or beside one of the longer veins, some- 

 times singly, but more often two or three together, the number 

 apparently depending upon the depth of the cavity formed by the 

 junction of the mid-rib and vein or the size of the rib or vein, but I 

 do not think they would, in Nature, usually be laid so thickly in one 

 spot as shown in the accompanying figure (PI. XI, fig. i). In colour 

 they are white with, perhaps, a delicate greenish tone, almost exactly 

 matching the colour of the leaf on which they are laid, and owing to 

 this and their position on the leaf they are exceedingly difficult to see. 

 Under an ordinary pocket lens — without which it is almost impossible 

 to detect them — they look smooth, to some extent shiny, and practi- 

 cally round ; but under a fairly high power they are seen to be flat- 

 tened at the top and at the base, very like an orange, and regularly 

 ribbed down the sides from near the top to the base, the small, un- 

 ribbed, flat space at the top no doubt containing the micropyle. 



In from ten to fourteen days from the time when they are laid the 

 eggs hatch and the young larva commences to feed on the back of 

 the leaf of its food-plant, the dewberry, eating only part-way through 

 and leaving the upper cuticle intact, so that in looking at the leaf 

 from above the presence of the larva is not easily discernible. It is 

 a most curious little creature, delicate greenish-white in colour, with 

 a row of large warts along each side of its back, from each of which 



