20 BRITISH LEPIDOPTERA. 



the mesothorax, and is extended along the pro- and metathorax, while 

 the coverings of the head separate into three pieces. The insect then 

 exerts itself to the utmost to extend the fissure along the segments of 

 the abdomen, and, in the meantime, pressing its body through the 

 opening, gradually withdraws its antennae and legs, while the skin, by 

 successive contortions of the abdomen, is slipped backwards, and forced 

 towards the extremity of the body, just as a person would slip off his 

 glove or his stocking. The efforts of the insect to get entirely rid of 

 it are then very great ; it twirls itself in every direction in order to 

 burst the skin, and, when it has exerted itself in this manner for some 

 time, twirls itself swiftly, first in one direction, then in the opposite, 

 until at last the skin is broken through and falls to the ground, or is 

 forced to some distance from it. The new pupa then hangs for a few 

 seconds at rest, but its change is not yet complete. The legs and 

 antennas which, when withdrawn from the old skin, were disposed along 

 the undersurface of the body, are yet separate, and do not adhere 

 together as they do a short time afterwards. The wings are also 

 separate and very small. In a few seconds, the pupa makes several 

 slow, but powerful, respiratory efforts, during which the abdominal 

 segments become more contracted along their undersurface, and the 

 wings are much enlarged and extended along the lateral inferior sur- 

 face of the body, while a very transparent fluid, which facilitated the 

 slipping off of the skin, is now diffused among the limbs and, when 

 the pupa becomes quiet, dries, and unites the whole into one compact 

 covering." 



One of the best detailed descriptions of the final larval ecdysis and 

 assumption of the pupal form that we know is that of Chapman. He 

 says {Ent. Record, ix., pp. 218-219) of Charaxes jasius : "The pad of 

 silk to which the larva suspends itself is made in a few hours ; the 

 actual pad is made by the larva withdrawing its head from the surface, 

 and so making a free loop of silk, longer than is necessary to reach 

 to the point at the surface to which it returns, and the repetition of 

 this process gradually forms the pad. It is always so placed that the 

 larva shall swing clear of all surrounding objects, and the latter is 

 never suspended, as are many Vanessid larvae, so that the pupa can 

 touch a vertical surface. It has a certain amount of surrounding spin- 

 ning, usually, apparently, with no other object than as standing room 

 for the larva whilst spinning the pad, but, in one instance, when the 

 suspension was beneath a leaf, certainly tending to prevent the leaf 

 falling off by spinning the petiole to the twig. The larva must fall to 

 the suspended position immediately, as I never saw one with its 

 claspers in position on the pad and still holding by the ventral prolegs, 

 a position held for many hours by most Vanessid larvae I have noticed. 

 As soon as suspended, the larva curls itself up into a ring, with the 

 mouth to the undersurface of the 8th abdominal segment, and main- 

 tains this position for tAvo or three days. 



" When the larva is ready to change, the coloured anal appen- 

 dages are visible through the larval skin. The first actual steps towards 

 the moult are very slight and slow in progress ; a certain amount of 

 movement is visible by depression or contraction of segments, some- 

 what rythmically, and apparently, as all these movements are, vermi- 

 cular, i.e., passing from segment to segment. During several hours, 

 however, the results are slight, just as the movements have been. 



