152 BRITISH BUTTERFLIES. 



by a fine white margin ; only at the outer margin of the hindwings, in cells 2 and 3, 

 is there evidence of a marginal line. (In European specimens this is absent.) The 

 brown-red spot, which is situated in the lobular appendage at the anal angle of the 

 hindwing is brighter, and in the female larger, than in T. w-albwm. This is thickly 

 edged outwardly and inwardly with white cilia, which, below are black. Not only 

 is the usual tail covered with glossy white cilia, but so also is the ill-developed tail- 

 like continuation of the fourth nervure. The underside is of a silky glossy grey- 

 brown colour ; the marginal fringes of a pale whitish. The white Theclid marking 

 of the underside is edged with darker internally, and, looked at sideways, appears 

 glossy. A series of intercostal spots on the f orewings between the margin and trans- 

 verse line, the spots increasing in size towards the anal angle. On the hindwings, the 

 imaginary extended series ends in lunules, which, outwardly, towards the margin, 

 incline to black. (In the European w-alhum this is only faintly indicated.) The 

 zigzag line forming the W does not complete the formation of the lower angles of 

 the letter W ; the points are broken partly by the ground colour, and partly by the 

 red-brown at the anal angle, mixed with a bluish band, which encroaches here on 

 the ground colour. At first sight this difference causes the insect to look quite 

 different from w-album, Between the red-brown band and the blackish-brown 

 margin is a silvery- white line. In the band, in cell 3, the black spot is very 

 developed ; above it, towards the inner angle, isolated spots are placed marginally ; 

 these become gradually paler and smaller, and are quite absent in European 

 w-album. Flies from August 13th-18th (FixsenJ. 



Pathological examples. — The following are the only pathological 

 examples of which we can find any record : 



a. An example bred in 1886 or 1887 from a larva found at Hazeleigh with 

 semitransparent hindwings (Raynor in litt.). 



/3. J . The right hindwing with a slightly pallid patch towards the outer 

 margin, and occupying the outer third of the wing. The underside of this wing 

 pallid towards the outer margin, giving the orange band on this side quite a yellow 

 coloration, the band on the left hindwing being normal in tint. [(Brit. Mus. Coll.) 

 Labelled " Zell. Coll., 1884."] 



Egg-laying. — The egg is laid on the twigs of wych elm, most 

 frequently, perhaps, at the junction of the current and preceding 

 years' growth, though this is by no means always the case, as, in some 

 instances, it is deposited at the base of a bud, and, occasionally, in the 

 fork of a main twig and a lateral shoot. It is, apparently, seldom laid 

 on a quite smooth surface of the bark, and the roughened and wrinkled 

 lines at the junction of two season's growth of wood are probably so 

 frequently chosen because the egg is there not only better concealed 

 from view, but also because the roughness provides a secure " foot- 

 hold," and reduces the risk of the egg being dislodged by winter 

 storms. The female would appear to be not infallible in her choice of 

 place for ovipositing, for I found an egg last autumn, which was laid 

 at the base of a leaf-stalk in such a position that it must almost certainly 

 have fallen to the ground with the leaf when the latter became detached 

 from the twig. Mature, flowering, trees are probably generally selected 

 for ovipositing, as most of the ova I have found have been taken from 

 such trees, neighbouring younger trees and saplings yielding very few 

 ova in the autumn or larvae in the spring. The embryo is mature 

 before the end of the winter, and an egg opened on January 13th, 

 1907, showed a fully-developed larva lying in a compact ring inside 

 the eggshell. The caterpillar, when it was removed for examination, 

 showed no disposition to walk, and, when released from an enforced 

 extended attitude, quickly resumed the curved position it occupied 

 when in the egg (Ray ward, in litt., January 19th, 1907). Newman 

 says that the eggs are laid on the twigs of Ulmus cam pest r is and U. 

 montana in July and August, being oblate-spheroid in shape, of a 



