SMERINTHUS OCELLATA. 431 



shining, covered with a very slight reticulation, the colour light, tender 

 yellow-green. Three or four days before hatching, the young larva can 

 be seen curled up, its colour not so green as the rest of the egg outside 

 it, and before long its red horn becomes conspicuous (Hellins). Bright 

 emerald-green, with a pearly lustre when first laid ('Bacot). Partheno- 

 genesis has been recorded in this species (anted, vol. i., pp. 27 — 29). 



Variation in eggs. — Hellins gives the following note on the 

 variation in the size of the eggs of this species : " The eggs of the 

 first and second days' laying were from i'8mm. to i^mm. long 

 and about i^mm. wide; those of the fifth day were i*6mm. long 

 and i - 2inm. wide; and those of the sixth day 1*4501111. long and 

 1 -2mm. wide, but these last shrivelled up and did not produce any 

 larvae." Poulton remarks that "darker ova produce larvae of a deeper 

 green, and vice versa." 



Comparison of eggs of Smerinthus ocellata and Amorpha 

 populi. — The eggs of A. populi are less full green, much paler, 

 more whitish-green and not so yellow-green as those of S. ocellata ; 

 also more circular (less oblong) in outline and plumper in build. 

 The surface is very finely netted, not at all so coarsely as the egg 

 of .S. ocellata, and looks almost smooth under a hand lens. [Eggs 

 of both species laid Tune 5th, 1899, and compared June 12th.] 



Habits of larva. — Hellins remarks that, whilst small, the larva 

 eats away both sides of a leaf of sallow or willow, leaving the 

 midrib untouched, and using it as a resting-place. Bacot notes 

 the larva, when small, as "resting on the midrib or on one of the 

 larger veins of the leaf, and having the power, like those of Mimas 

 tiliae and Sphinx ligustri in their early stages, of dropping on a 

 thread, if by any chance it loses its hold. It assumes the 'Sphinx' 

 attitude in its 2nd instar, and rests attached by the 4th pair of prolegs 

 and anal claspers only, the other three pairs of prolegs being 

 withdrawn until flush with the ventral surface of the body ; as the 

 larva gets larger it rests, as a rule, on an upright twig, which it 

 grasps with its anal claspers, and with the last pair (or last two 

 pairs) of prolegs, assuming an upright attitude, with the fore-part 

 of the body raised, and the head drawn back. In this position its 

 resemblance to a sallow- or willow-leaf is very perfect (see, anted, i., p. 

 80), and the reason for the withdrawal of the unused prolegs is ap- 

 parent, as, if not withdrawn, they would break the regular leaf-like out- 

 line. Occasionally one finds larvae at rest on the midribs of partially 

 eaten leaves, and, in that position, they do not raise the fore-part 

 of the body, and they use all the prolegs." Newman states that 

 the larva rests on a twig of its foodplant, attached by the 2nd, 

 3rd and 4th pairs of prolegs and anal claspers, elevating the fore-part 

 of the body • the head prone, the mouth touching the first pair 

 of legs, all the legs crowded together and directed forwards • the 

 larva never falls from its foodplant or feigns death, unless its statuesque 

 immobility may be so interpreted. Zeller remarks ( Stett. Ent. 

 Zeit., xxx., p. 386 ) that the larva of S. ocellata assumes a quite 

 different posture when at rest from those of M. tiliae and A. populi, 

 &c, and that Rosel has given a very natural figure of it. He 

 has no doubt that the many near relatives of S. ocellata share this 

 habit. At Carlisle, larvae are found freely on the osiers, which fringe 

 the small streams (Day) • on dwarf sallow in a bog at Enniskillen 



