POLYOMMATUS ICARUS. 195 



on the move on February 17th, 1908. Keference may be made here 

 to the question of the difference in habit of larvae hatching in June. 

 Sometimes a batch of June larvae feed up entirely, and produce 

 imagines at end of July, August, or early September, according to the 

 season ; other batches will subdivide into two, one section of the 

 larvae feeding ahead, and producing imagines in August or September, 

 whilst those of another section of the same batch, treated in exactly the 

 same manner, grow much more slowly, and, having reached the 3rd 

 in star, resolutely refuse to make progress, and, in this stage, hybernate, 

 and re-commence to feed again in February and March. Sometimes a 

 batch will subdivide into three sections, one set producing imagines in 

 July and August, another in September, the third only reaching the 

 3rd instar, and hybernating as larvae in that stage. The larvae from 

 the eggs laid in July, August, and September all feed up till they 

 reach the 3rd instar, in October, and then hybernate with the laggards 

 from the eggs laid in June. Prideaux notes (in litt.) that ova laid on 

 June 18th, 1900, gave larvae on June 29th, the larvae feeding well for 

 a few weeks on pods of Lotus, that all then, with one accord, ceased 

 feeding entirely, although offered various other Leguminosae, but 

 remained alive, about a quarter grown, and were in this stage in 

 October onwards. Kayward observes (in litt.) that the larvae from a 

 batch of ova laid by a Cornish £ , at the end of June, 1907, all laid 

 up for hybernation early in August, and could not be tempted to 

 continue feeding, although kept in a warm room. He further states 

 that, in feeding, the larva invariably in its earlier stages, and usually 

 throughout its life, eats the cuticle only of the leaves of its foodplant, 

 leaving the veins and midrib, in this respect resembling the larva of 

 Aricia astrarche, and differing from those of Agriades coridon, and A. 

 thetis (bellargus), which, in their early stages, eat round holes com- 

 pletely through the entire substance of the leaves. For hybernation, 

 he says that, in confinement, on cut stems of foodplant, the larvae 

 take up positions on the underside of the leaves, and do not appear to 

 seek the lowest or most secluded parts of the plant ; larvae kept in the 

 open on a growing plant of Lotus comiculatus during the winter of 

 1906-7, however, were found early in March hybernating low down 

 close to the roots of the plant. Two or three larvae kept in a glass- 

 topped metal box during the autumn of 1907, left the food and laid 

 up for hybernation in the angle formed by the side and bottom of the 

 box ; in nature, a sheltered position near the roots is probably always 

 chosen. The hybernating stage takes place, he adds, in his experience 

 always at the 3rd instar. Hybernation, after the first warm days of 

 early spring, however, appears soon to end, and Hellins notes that, on 

 February 5th, 1876, he had one larva more than half-grown, whilst, 

 in 1881, Buckler found larvae feeding again, after hybernation, on 

 March 18th. One would suspect that the early one noted by 

 Hellins, like the one that Chapman observes as pupating on March 

 24th, 1908, was influenced by confinement. At any rate, larvae are 

 usually still small at the end of March, although the transparent 

 blotches in the leaves of the foodplant are pretty easily seen, and they 

 are not, as a rule, fullfed until May or early June. Hellins observes 

 that, when moulting, the larva of this species does not eat its cast 

 skin. Buckler notes (Larvae Brit. Butts., i., p. 194) that Jordan had 

 often found the species hybernating as a larva in Devonshire, when 



