74 BRITISH BUTTERFLIES. 



of E. ida and E. pasiphae often leaving the foodplant, and concealing 

 themselves under dead leaves or twigs close to the grass, sometimes 

 quite on the ground. Of other butterfly larvae that feed by night, and 

 rest hidden during the day, one may notice those of Tliais polyxena var. 

 cassandra, and Thais rumina var. medesicaste, which, during the day, rest 

 concealed on the underside of leaves of their foodplant or those of 

 other plants growing near their food ; the larva of Thais medesicaste, 

 in its last stage, often hides under stones around the roots of its food- 

 plant, or amongst the stones of walls out of which the plant sometimes 

 grows. Our own impression, too, is that the larvae of Pyrameis cardtii 

 and P. atalanta also mostly feed by night, remaining practically still 

 during the day, but, as both the resting and feeding is done within 

 their tents, it is difficult to make certain that this is so. Sic.h observes 

 that captive larvae of P. cardtii were several times observed feeding by 

 day within their tents. 



We have already noted that certain larvae choose an exposed 

 position on which to rest between their meals, and have instanced 

 the larva of Char axes jasius (antea, p. 72), and it is interesting further 

 to note that the larva of this species feeds naturally by night, in spite 

 of its exposed position of rest by day. With regard to this, Chapman 

 observes that the larva of 0. jasius, " between its meals, rests on the upper- 

 surface of a leaf, or of several leaves fastened together by the silken 

 carpet with which it clothes their surface, and which is necessary to 

 give it a firm foothold," etc., Powell adding that the meals are taken 

 by night and are of comparatively short duration ; whilst, the larva of 

 Basilarchia archippus, Scudder says, "eats the nearest bit of the 

 leaf on which it finds itself, down to, but not including, the midrib, 

 first on one side and then on the other, retiring near the tip of the 

 midrib to digest it ; it takes its subsequent meals in the same way, 

 moving with excessive deliberation along its narrow path, and returning 

 always to the same spot. On this perch, it cannot be seen from below, 

 and, from the sides and above, seems almost or wholly a part of the 

 denuded mibrib to which it clings, more particularly when the leaves 

 are set in motion by the wind, as they usually are on the trees on which 

 it feeds, particularly in the case of the aspen." The resting-habit of 

 the larva of Char axes jasius is closely paralleled by that of Apatura iris, 

 which covers a leaf of sallow with silk, on which to rest when not 

 feeding ; when thus resting, its head points towards the leafstalk. 

 Feeding takes place much of tener by night than day, the larva quitting, 

 for this purpose, the silk-covered leaf, to take a rapid meal, and return- 

 ing again to the same place to rest (Buckler). The larva of Iphiclides 

 podalirius also appears to feed almost entirely by night, and to rest 

 exposed after feeding, often returning to take up the same position on 

 a stem or branch to rest between its meals; this position is usually 

 well up on a branch, where its colour and resemblance to a leaf 

 make it very difficult to see, without pulling down and examining the 

 branch closely. 



Most larvae of Papilionids, however, feed by day, but none the less 

 take up a very definitely exposed position on their foodplant, between 

 meals, e.g., the larvae of Papilio machaon, V. alexanor, and P. hospiton, 

 and Scudder notes that the caterpillars of some of the Nearctic Papilionids 

 have a favourite place of repose to which they retire after every meal, 

 and which they carpet with silk, the larvae resting upon the middle of 



