76 BKITISH BUTTEKFLIES. 



their tents during both their feeding- and resting-periods. Of 

 these two species Scudder says, " the larvae remain within their 

 dwellings, eating away the leaves that form them, until, having 

 practically destroyed them, they are obliged to leave them and con- 

 struct others; whilst many of the gregarious species, e.g., the Melitaeids, 

 Vanessids, etc., utilise their common webs as feeding-places and 

 hiding-places combined, continually extending their homes to take in 

 new leaves, which, when partially eaten, become absorbed in the ever- 

 growing mass of half -eaten leaves and f rass which the web encloses. The 

 larvae of " skippers " also hide in specially prepared chambers between 

 the times at which their meals are taken." Of the Vanessids, Powell 

 notes (in litt.) that " the young larvae of many species live and hide in 

 webs, but when half-grown they rest exposed in groups, the members 

 of a group feeding by day and resting almost simultaneously; later on, 

 they scatter to a considerable extent, and especially is this noticeable in 

 Vanessa io and Aglais urtlcae; the larva of Polygonia ecjea also feeds 

 by day, resting exposed between its meals, whilst those of Melitaea 

 aurinia and M. cinxia live w T hen young in a web, feeding outside and 

 resting and sunning during the day, and seeking the shelter of the web 

 in bad or cloudy weather, and at night ; when older they still feed by day 

 and rest on stems of their foodplants, etc., fully exposed, whilst the 

 larvae of M. didym.a and M. cleione also feed by day, exposed, but usually 

 hide during the resting-periods between their meals on the undersides 

 of leaves." 



The second resting-period of butterfly larvae to be noticed is that 

 connected with the exuviation of the larval skin. This is often a most 

 exhausting process and considerable care is exercised by the larvae in 

 the choice of a suitable place for the purpose, so that, whilst the larva 

 is in the tender stage of a new skin, accident shall not befall it, nor 

 shall it be conspicuous to the enemies always ready to devour it. 

 Hence, after a larva is fullfed in a certain stage, a place of safety has 

 to be sought, and a silken platform spun, in which the prolegs are 

 securely fixed, so that no injury due to slipping or falling may take 

 place. Usually this resting-period lasts from two to three days, during 

 which time the new larval skin, and its attendant structures, are 

 formed beneath the old skin, the lubricating fluid between them is 

 developed, and the final process of exuviation and after-rest, during 

 which the skin is hardening, take place. 



The period of rest varies in connection w T ith each moult, and usually 

 takes much longer in cool weather than in warm. Thus the larva 

 of Charaxes jasius rarely occupies more than two days in moulting 

 during summer, whilst, in winter, it falls little short of a week. The 

 larva of Erebia zapateri, at its 1st moult, occupied from January 31st 

 to February 6th, 1906, whilst for the 4th moult, in April, it occupied 

 only four days. The first moult of Papilio macliaon takes fully two or 

 three days, the later moults perhaps a little less, the larva of Papilio 

 alexanor occupies on an average about two days (Powell) ; the moults 

 of Pontia daplidice are, as a rule, very rapid ; one larva settled down 

 at noon, September 9th, 1906, moulted 10 a.m., September 10th, 

 1906, and started to feed about noon, in no case did any moult for 

 this species occupy 48 hours, and a larva spun up for change on one 

 day had always moulted before the expiration of the following day 

 (Sich) ; the 3rd moult of a larva of this species occupied only one day, 



