210 



BRITISH BUTTERFLIES. 



only shelter the oak branches from northerly exposure, but even reflect 

 the sunshine on to them. At this spot, one little double twig, 6 inches 

 long, was found with six eggs, of which two were close together on a 

 small twig on the side of it, next. the main branch. On several other 

 occasions two eggs were found on one twig, but always far enough 

 apart to make it probable, if not certain, they were not laid at the 

 same time. These two were also probably laid at different times, the 

 immediate positions being obviously very attractive ones. ' One or two 

 eggs were found with minute holes in them, too small for a larva to 

 have emerged from, and concluded to be caused by a hymenopterous 

 egg-parasite ; another egg, apparently whole, was found, when broken, 

 to be empty except for some mites. A sound egg opened, presented a 

 quite mature young larva (Chapman). The eggs are usually laid upon 

 an oak twig, upon which, in spite of their colour, they are not con- 

 spicuous, each looking like a small, inconspicuous, fungoid growth 

 (Tutt). Bignell notes (Ent., x., p. 285) that, on August 29th^ 1877, 

 he saw a $ at rest on a sallow-bush ; pulling down the branch very 

 carefully he observed that she had deposited an egg on the leaf on 

 which she rested. Having boxed the ? she obliged him with another 

 egg, which, being compared with the first, was found to be identical. 



Ovum. — The eggs are of a bluish-grey colour, varying a good deal 

 in tint, some rather white. They suggest that, when fresh, they were 

 probably white, but gradually acquire a dark tint from rain washing 

 on to them the carbon of honeydew and other colouring matters. 

 Sometimes their colour matched their surroundings so as to make 

 them difficult to see, other specimens were more conspicuous, as pale 

 grey against brown ; it is very probable that those whose colour 

 assimilated best to their position very often escaped our observation. 

 There is one other reason for their being at present darker than one 

 suspects they were at first ; this is the development of the contained 

 larva, which is dark in tint, and the eggshell proper is a good deal 

 exposed between the walls of the outer raised network, which itself 

 probably takes a tone also from its background. Seen under a hand- 

 lens, the egg looks as if covered with a felting of fine wool or hairs, 

 but a higher magnification shows that the rough coating is a raised 

 netting, usual on Ruralid eggs, with knobbed projections at the angles 

 of intersection. The egg is 08mm. wide and 0-42111111. high. These 

 dimensions are to the outside of the ornamental coating, the true egg is 

 decidedly smaller, perhaps 0-75mm. and - 37nim., probably a little less. 

 Looked at from above, the egg shows a central depression 0'12mm. in 

 diameter. The bottom of this shows a fine network of small cells 

 (the reticulation of the eggshell proper?). There is a central cell, with 

 about seven surrounding it, as a rosette, in the usual way, and round 

 this about four circles of cells iill up the space to the margin. The 

 walls of the cells arc comparatively wide (or thick), so that the cells, 

 though arranged approximately hexagonally, are each circular, or 

 nearly so. The four circles are regular in places, but in others so 

 broken that there is, in fact, no complete circle, and one doubts 

 whether they tend to be three, four, or five oircles, or are, perhaps, an 

 approach to a spiral. All the cells — the central one, those of the 

 rosette, and the others- are of fairly uniform si/A 1 , r/:., about O'Olinm. 

 The eggshell, as seen in the interspaces of the superficial layer, is 

 somewhat obscured, but seems to present cells of very similar size and 



