286 BRITISH BUTTERFLIES. 



depression of small circumference (Wood, Ent. Rec, viii., p. 186). 

 The ego- forms a portion of a sphere about 0-66mm. in diameter at the 

 base and 0-33mm. in height ; it is white, and, according to Volker, 

 possessed exactly the same tint on March 7th, 1906, as it did when 

 •deposited (" a dull porcelain-white ") ; it is thickly covered with pits 

 (depressions). Each depression forms a six-angled cell, the points at 

 the six angles extend vertically outwards into a short projection. The 

 cells are often not regularly formed but often deformed ; the cells and 

 pits also vary in size. The best illustration in this respect is offered 

 by the cells on the shoulder. The base of the cells appears dark and 

 lies somewhat deeply. The micropylar cell at the apex is the largest 

 and deepest. This egg covered with these pit-like cells down to the 

 base gives an impression of an Echinus, the spines of which are 

 represented by the projections at the corners of the cells. (Magnified 

 100 diameters ; described March 9th, 1906.) (Gillmer). 



Habits of larva. — A larva hatched on March 24th, 1907, was 

 placed on early plum (species used for hedges), and on this soon made 

 itself at home on a second leaf that was still rolled up into a close 

 cylinder, not attacking the first leaf that was well expanded. Here it 

 ate portions of the whole thickness of the leaf ; at first it got into the 

 end of the cylinder from the tip, and was nearly hidden, afterwards 

 (28th), it was on the outside. Like all these young Lycasnid larvae 

 (Plebeius aegon, Heodes virgaureae, etc.), it was very difficult to examine 

 without injuring it, as no matter how quiescent it was, as soon as 

 brought into a sufficiently strong light for observation, it began search- 

 ing for some way of getting into the shade. By March 29th, it had 

 fed up a good deal, and was then more easily examined. It moulted on 

 April 6th, when it ate all the cast skin except the head. By April 10th 

 the larva was much grown, now nearly 6mm., and the colours much 

 more clearly differentiated. When fullgrown in the second instar, the 

 larva is in form and colour almost identical with the adult larva. On 

 April 17th, the larva was eating vigorously, and, by April 23rd, 1906, 

 had spun a pad of silk, and was apparently resting for its third moult. 

 By the morning it had moulted, but had not eaten its skin, and, as the 

 larva died when nearly fullfed, its debility was attributed to not having 

 eaten this skin. In its last instar, the larva nearly always rests under 

 a leaf, and eats either the sides or end of a leaf, but always goes to a 

 whole leaf to rest. The difficulty of finding this larva of over half an 

 inch long, on a little bit of sloe with 20 or 30 leaves is quite ridiculous. 

 In looking for it, one sees its dorsal ridge in profile, it proves to be a 

 margin of a leaf ; one sees its " slope," it is the light shining through 

 a curled portion of a young leaf ; one sees it half-a-dozen times in 

 this deceptive fashion before actually spotting it. Then one wonders 

 how one could have missed it so long, it is so obvious, and taken 

 altogether, not at all like a sloe leaf. Yet any view of the group of 

 sloe leaves, gives several items that are very like portions of the larva 

 (Chapman). Mathew says (in lift.): "In the autumn of 1900, 

 Mr. Cornell sent me 30 or 40 ova of B. betulae which he had obtained by 

 searching sloe-bushes in Epping Forest, and, upon examining these, 

 on April 27th following, I found three of them had hatched, but could 

 not discover the larvae. No others emerged until May 9th, and by the 

 11th, they had all hatched, so I rather suspect the three found to have 

 emerged on April 27th, might have been eggs of the previous year. On 



