THE RESTING HABITS OF BUTTERFLY LARVAE. 77 



September 3rd-4th, 1882, the 4th moult occupying two days, 

 September 8th- 9th to September 10th- 11th (Buckler) ; the average 

 resting-period of Colias edusa at a moult is about two days, and so 

 on. As to the exhausting nature of the moult in the larva of Dryas 

 paphia. Buckler notes that one, that moulted April 29th, 1877, waited 

 four hours before moving, and then hid itself under another leaf, 

 remaining there without further movement for 29 hours more ; a later 

 moult in May took some days, the larva being fixed for the process 

 on May 20th, the actual moult not taking place until May 25th. 



Scudder says that the moult from larva to pupa occupies a greater 

 time than the moult from one larval stadium to another. This is, 

 perhaps, pretty generally the case, but by no means always so, for, 

 whilst the larva of D. paphia takes at least from four to six days' rest 

 for its ordinary larval moult, it rarely takes more than 24 hours after 

 suspension, when fullfed, before pupation takes place, e.g., a fullfed 

 larva suspended June 8th, 1877, pupated June 9th ; a similar rapidity 

 is noticeable in Brent/as selene, a larva of which suspended itself on 

 August 6th, and pupated August 7th, 1870; and larvae of Melitaea 

 athalia .suspended on May 24th-25th, pupated May 26th-27th. 

 Similarly larvae of Papilio machaon have a somewhat short quiescent 

 stage preceding pupation, the larva resting about one and a half days 

 from the time that the girth is spun and the position for pupation 

 taken up, before assuming the pupal stage. Also, larva? of Pieris 

 napi spun up on July 4th-5th, 1874, became pupae on July 6th-7th, 

 and the larva of Leptidia sinapis also takes two days after spin- 

 ning up before pupation actually occurs (Buckler). A larva of 

 Pontia daplidice, had spun its silken platform and was spinning 

 its girth at 4.20 p.m. on September 20th, 1906 ; by 5.5 p.m. the 

 girth was finished, and, after inspecting the bosses, it settled down 

 to rest for pupation ; the resting-period lasted till 5 p.m. on the 22nd ; 

 the larva becoming a pupa between 5 p.m. and 6 p.m. In the evening 

 of June 4th, 1906, a larva of Pieris brassicae selected a spot for pupation 

 and spun part of its platform; at 10 a.m. on the 5th, the platform was 

 finished, the girth spun, and the larva had entered the resting-stage ; 

 at noon, on the 7th, the larval skin had just been cast and pupation 

 completed. On the evening of June 10th, 1906, two larvae of Pyrameis 

 cardui were spinning silk ready for pupation ; at 7 a.m. on the 11th, 

 they were both hanging from their silken pads, between 2 a.m. and 

 10 a.m. of the 12th, both had changed to pupae (Sich) ; another larva of P. 

 cardui, fullfed on October 10th, suspended itself on the 11th, and 

 became a pupa on the 13th ; a larva of Euvanessa antiopa, fullfed July 

 30th, suspended itself on the 31st, and pupated August 2nd (Buckler). 



In none of these has the quiescent resting-period, preceding 

 pupation, lasted more than two days. The larva of Limenitis sibylla, 

 however, has a quiescent period of three days, whilst that of Apatura 

 iris has one of four days. The fullfed larva of L. sibylla suspends 

 itself by the anal prolegs, hangs with its body downwards in a sinuous 

 curve, with its head bent a little upwards, remains motionless for 

 three days, then, swinging itself to and fro and stretching downwards, 

 the larval skin splits and pupation takes place. The fullfed larva of 

 Apatura iris spins a large pad of silk under a leaf to which it attaches 

 itself by its anal prolegs, remains motionless for about four days, when 

 it releases its hold, hangs suspended, pupation taking place in about an 



