882 



BRITISH BUTTERFLIES. 



to be deceived by appearance. She had correctly determined the plant 

 as sorrel, notwithstanding the fact that every leaf had been completely 

 eaten off, leaving only the bare stalks, and it was upon one of these 

 she laid her egg, and on the underside ! I never saw more than one 

 egg laid on a leaf, and only once two laid on the same plant ; the 

 female that did this laid four eggs at one bout, commencing with these 

 two on one plant, and then crawling across a dry cowpad to two other 

 little plants, laying one on each. I kept four ova from different 

 females, three only hatching five days after being laid. Two of the 

 larvae are still (October 2nd, 1906) alive, and growing very slowly." 

 Newman says that " the egg is laid on the leaves of several species of 

 Rum ex as R. obtitsifolius, R. pulcher, R. acetosa, R. acetosella (docks 

 and sorrels)." Merrifield also says that eggs are laid, in confine- 

 ment, on dock or sorrel. Buckler, that they are laid on leaves of 

 Rumex acetosella. [Bromilow notes (Soc. Ent., viii., p. 178) that 

 he observed a 2 laying her eggs on the dry leaves of Trifolium 

 filiform e t near Vence-Cagnes, in the Nice district, on April 4th, 1893 ; 

 the two bluish- white eggs he found were round, with a flattened base, 

 by which they were attached to the underside of a leaf.] For 

 Scudder's note on the subject, see antea, p. 344, and for the length of 

 the eggstage in the different broods in North America, see antea, pp. 

 345-346. 



Egg-Parasites. — Scudder says that the eggs are attacked by one of 

 the little egg parasites, Telenomus graptae, which emerge through one 

 of the lateral cells of the egg. 



Ovum. — The egg is 0*61mm. in diameter, and less than 0-3mm. high, 

 just a little less than a hemisphere. If it varies from a hemisphere in 

 form, it is in the direction of having been rather more than a hemisphere, 

 but a little sunk and flattened on top, a little bulging at the top of thesides. 

 At first glance it appears to be pure white, but, on closer examination, this 

 appears to be due to the sculptured .surface, a very evident underlying 

 green occupying the hollows. The surface is covered with large 

 (comparatively to size of egg) hollows, of approximately spherical 

 surface, each hollow 100° to 120° of a sphere in diameter. It is not, 

 perhaps, self-evident in R. phlaeas, but is so nearly so in the similar egg 

 of Heodes virgaureae, that it may be assumed that there is a simple dome- 

 shaped eggshell, and that the sculpturing is in a frothy or corky layer 

 superficial to this. Probably, its whiteness is due to the inclusion of 

 minute air bubbles. These superficial hollows vary a good deal in 

 different eggs ; usually they have a spherical surface, but now and 

 then they appear to have a flat bottom, i.e., down on the real egg- 

 surface, and the divisions between them are more walls than portions 

 of a continuous solid layer. The relative sizes of the hollows at 

 different parts of the egg also vary a good deal, especially about the 

 micropylar region. In some, the micropylar region is the bottom of a 

 cell that looks much like the rest of the cells. In others it seems to 

 be a special hollow, surrounded by smaller cells. In all cases, 

 probably, the micropylar area is the surface of the eggshell proper, 

 free from the frothy coating that affords the general sculpture, and 

 this area may have more or less the aspect of one of the hollows of 

 this sculpture. A specimen mounted in " balsam " seems to show this. 

 It happens to be one with very large cells to the general sculpture, 

 0-15mm. or 0*16mm. in diameter, in one or two of those measured. 



