64 BRITISH BUTTERFLIES. 



mature rapidly and pupate early, remaining in the latter stage for some 

 10 months out of 12. They are also as lethargic as the larvae of the Callo- 

 phryids, and Chapman notes (Ent. Bee, xvi.,p. 278) that alarva of Thestor 

 ballus under observation, apparently at rest, was really busily eating, 

 the front segments raised from the stem of Lotus on which it rested, 

 whilst, in its true legs it held a flower-bud of the plant, which it was 

 munching vigorously, and which disappeared in about a minute ; the 

 head was quite bent under so that the mouth-parts were directed 

 backwards. The marginal flange in this attitude hangs down like a 

 curtain, so as completely to hide not only the head and legs, but also 

 the small flower-bud that was being eaten ; the motionless reposeful 

 appearance of the larva whilst eating rapidly was very striking. 



The Thestorids and Callophryids appear to have a very marked 

 objection to producing " forward " larvae, at whatever latitude or 

 altitude they may be found, for the Thestorids are essentially 

 inhabitants of the warmest temperate regions, and Callophrys rubi is 

 apparently as completely single-brooded in Algeria and southern 

 Europe, as in Finland and Lapland. On the other hand, at least two 

 Nearctic " hairstreaks," with the same habit as these so far as hybernat- 

 ing in the pupal stage is concerned, that inhabit, however, fairly low 

 latitudes in the United States, produce " forward " larvae, viz., Uranotes 

 melinus that appears to be continuously-brooded in the south, and 

 double- brooded farther north, and Mitura damon, certainly triple- 

 brooded in the south, double-brooded and partially double-brooded 

 farther north, according to latitude. Of this latter species, which 

 feeds at the tips of sprigs of Juniperus virginiana, Scudder notes 

 (Butts. Neiv Engl., p. 866) that the colour of the larva is so exactly of 

 the same rich green as the plant on which it feeds, that it is admirably 

 protected. When feeding, the head is covered by the prothorax as 

 with a cowl, so that one would not know it was at work but for the 

 regular muscular movements of the body. 



The Strymonid larvae are very uniform in their habit of hybernating 

 within the eggshell, of feeding in the spring and early summer, of an 

 entire absence of producing "'forwards," whilst they show some 

 variety in the food-habits, although usually restricted to tall shrubs 

 and trees. The larvae of our two British Strymonids — Strymon pruni 

 and Edwardsia w -album — are somewhat similar in their habits ; they are 

 both external-feeders, yet, bore into their food when young, burying 

 the head and neck ; later they cling somewhat tenaciously to 

 the upper- or underside of a leaf, eating holes through the leaves on 

 which they rest, and, whilst eating, appear to be quite still and immov- 

 able, there being practically no movement of the body buried beneath 

 which, and quite out of sight, the larval head and neck may be 

 actively reaching for and devouring its food. The larvae of both 

 species, too, have a very slug-like habit of walking, but their safety lies 

 in their habit of resting for along time immovably in the same position 

 on a leaf. Of the larva of E. w-album., Bird observes that it prefers 

 to rest on the underside of a young leaf of wych-elm, growing at the end 

 of a twig, clinging by its anal claspers to the midrib at the bottom of 

 the leaf, the body resting on the leaf alongside the midrib which is exactly 

 the same position as that taken by a young folded leaf of the wych-elm, 

 so that, at first glance, one can hardly tell one from the other. The 

 larva of Strymon pruni, on the other hand, appears to rest on the upper- 

 side of a leaf, but hides so successfully that, when larvae can be beaten 



