304 BRITISH LEPIDOPTERA. 



less delicate and transparent ; soon afterwards the ovum is opaque, 

 yellowish, and mottled with bright green (Poulton). Broadish oval 

 in outline, plump, about 1*7 5mm. long, and varying in width, some 

 1 -45mm. wide, others 1 "25mm. The shell is rather glossy, smooth, in 

 colour a palish tint of full green. Before hatching the dark horn of 

 the larva shows through the shell '(Hellins). 



Reputed parthenogenesis in S. ligustri. — Clogg records 

 (JLnt., v., p. 357) that he obtained eggs from an unimpregnated 

 female at East Looe in 187 t, that 63 larvae hatched between July 2nd 

 and 6th, that he kept 10, gave away 15, and set free 38. All the 25 

 larvae kept in confinement pupated, and 12 moths emerged, all barren 

 females. Nix notes (Ent., iv., p. 323) that, in 1869, he had some eggs 

 from a bred $ that had no intercourse with a g , but that the eggs 

 all hatched. See also antea, vol. hi., p. 381. 



Habits of larva. — The young larvae eat their egg-shells in part; 

 the amount eaten varies, but appears never to be more than three- 

 quarters of the whole, and often there is an aperture barely large 

 enough for emergence. The young larvae spin webs for foothold, and 

 readily suspend themselves by threads. This fact has already been 

 observed by Kleemann, and it is very interesting as the habit is so 

 entirely abandoned later, although it appears again before pupation. 

 The disappearance of this habit probably follows from the great size 

 and weight of the larva, which renders this method of attachment and 

 suspension comparatively useless. It is of especial use when the 

 larva clings to the flat underside of the leaf at any point except (that 

 usually selected) the projecting midrib. Later the larva gains 

 security by the extreme power of its claspers. . . . The protective 

 resemblance of the young larva is to the underside of the leaf, and the 

 larvae are especially hard to distinguish when seated on the midrib, and, 

 in this position, they seem nearly always to rest. In the second 

 stadium the larva still rests as a rule on the midrib of the under- 

 side of a leaf. After ecdysis the skin appears always to be 

 eaten, except the head and horn, which seem to be invariably 

 rejected. In the third stadium the larva habitually rests in the 

 Sphinx attitude upon the midrib, this position being assumed, 

 although exceptionally, in the second stadium and is even seen 

 in the first. The fourth stadium is, however, the stage of the 

 Sphinx attitude, and the head is held higher and further back 

 than at any other time, the position being possibly even less 

 striking in the final stadium (Poulton). Reaumur notes 



( 'Memoires, ii., p. 253) that the usual resting position of a larva 

 is to hold a branch tightly with the crochets of its prolegs, the 

 part of the body carrying the prolegs being pressed to the 

 branch, whilst the anterior part is thrown back, and is held almost 

 perpendicular to the branch — resting for hours immovably in this 

 attitude. We have already detailed at length (antra, vol. i., p. 

 51) the meaning of the Sphinx attitude as developed so strongly 

 in the larvae of this superfamily, and those of some closely allied 

 groups. It appears to be clue to the strain caused by gravity upon the 

 anterior unsupported part of the body, together with the compensating 

 muscular reaction. It is most marked in the vertical position of the 

 larva with the head upwards, and also in the horizontal position wih 

 the head downwards, and least of all in the position of the Sphinx — 



