242 



BRITISH BUTTERFLIES. 



diameter of the egg. The diamond -shaped or rhomboidal cells are 

 smaller at the top, and form approximately about sixteen rows from 

 the apex to the base (Tutt, January 18th, 1897). Of the shape 

 common to the Lycaenids, but larger than that of any of our British 

 species of "blues," e.g., its wide diameter compared with that of the egg 

 of Celastrina argiolus, is as 4 : 3, and this, of course, indicates a con- 

 siderable increase of bulk ; it is round in outline, flattened, and, with 

 the exception of a central depression on the upper surface, covered 

 with irregular oblong reticulation, the lines of which, much more 

 prominent on the top than in any of the "blues," on the sides become 

 so exaggerated that, at the knobs, they stand out like spines, and the 

 egg looks quite like a rough Echinus in miniature. The undersurface 

 which rests on the leaf (or stem) is only granulated ; the shell under 

 the reticulation apparently has a very pale pinkish-brown tinge ; the 

 lines of the reticulation are whitish (Hellins). 



Habits of larva. — A larva that hatched on April 1st, 1907, was 

 placed on a hardly developed leaf of Quercus pubescens about *75in. long. 

 At this stage, the leaves of this oak are densely felted with hairs. 

 On April 2nd the larva was half buried in the felting, and ejecting a 

 few pellets of frass. On April 3rd, there is nothing visible of the larva 

 but its anal claspers, the rest being buried in the felt as in a mine, and 

 quite invisible ; above the claspers is a little pile of pellets of frass. 

 When nearly fullfed, in the first instar, the larvae burrow under the 

 tomentum, preferably from below ; they also burrow in the thick 

 young tissues, but do not bury themselves beyond a segment or two, 

 eating, however, the whole leaf thickness except one surface. A larva 

 in the second instar, placed on a fresh young leaf -75in. long, began 

 at once to dig into the centre of the broken midrib. When about half- 

 grown and on young oak-shoots the larvae of both Bithys quercus and 

 Nordmannia ilicis have a habit of hiding by burying themselves on the 

 upperside of a leaf, along the midrib, the petiole being too short to 

 count, with the head pushed as far as may be into the axil. In this 

 position they are remarkably invisible, the oak at this stage having both 

 greens and red-browns, to which these larvae closely assimilate (the larva 

 of N. ilicis green, that of B. quercus brown) (Chapman). When in the 

 third instar, it is almost impossible, without the closest search, to see 

 the little B. quercus larvae on an oak-twig with the young leaves and 

 blossoms of the oak just bursting, the stipules and bracts, with their 

 dull brownish tint, being almost exactly of the colour of the young 

 larvae. They appear not to dislike getting on the blossoms, but on the 

 leaves they seem to prefer the edge or underside, and eat tiny holes 

 through the surface of the leaf. They are slow in their movements, 

 and maintain a fixed position for a considerable time. The small 

 larvae here noted were received from Raynor, May 11th, 190G (Tutt). 

 The larva' certainly eat their cast skins at each moult, as only the 

 heads can be found. When preparing for its moult from the third to 

 the fourth stadium, a larva under observation spun a little pad, but also 

 fastened down a tew surrounding bracts, etc., so as to form a little 

 nest. The fastening down is, as it were, accidental, not due to pulling 

 I lie bracts, etc., into place, but to the larva having crept in amongst 

 them, and so the spinning of the pad has retained them where they are 

 (Chapman). The larvae feed up pretty rapidly, varying somewhat accord- 

 ing to season, and are usually fullfed in early June, at which time they 



