96 



THE ENTOMOLOGIST. 



pair of yellow spines is a conspicuous feature. It is remarkable 

 that the pair of fleshy horns that can be extruded behind the 

 head are proportionately very much longer in the young cater- 

 pillars. 



When preparing for the chrysalis stage, the caterpillar first 

 secures the leaf to the twig on which it grows with a quantity of 

 brown silk. Next it spreads a patch of the same material on 

 the leaf below, in order to give a secure hold to its hind claspers. 

 Then having placed itself in position with its tail on this patch, 

 it proceeds to fix a thread to the leaf on one side of its body ; 

 then letting go with its legs and also the first pair of claspers, it 

 rears itself up at right angles to the leaf, and throwing its head 

 back, it protrudes the second and third pairs of legs ; then 

 passing its head across to the other side, it lodges the thread 

 between the first and second pair of legs, and as the head 

 descends again to the leaf on the other side, the disengaged 

 portion of its body is bulged out in the opposite direction, 

 carrying the thread with it. When the head reaches the leaf, 

 the thread is glued either to the spot from which it started, 

 or a little to one side of it. The thread having been made 

 fast, the head is gradually raised again, and the whole ma- 

 noeuvre gone through in the opposite direction. The new 

 thread is guided by one or other of the first pair of legs and so 

 kept parallel with and touching the loop just made. This 

 process is repeated backwards and forwards, the loop being kept 

 taut all the time by the bulging of the body, until it is 

 sufiiciently strong. When complete the head is pushed under 

 the slack loop, which is gradually worked backward until it is 

 arranged to lie in the groove between the fifth and sixth 

 segments, counting from the head. In about twenty-four hours' 

 time he lets go with everything except the hind claspers, and lies 

 back in the loop. About the third day the skin is ready for 

 sloughing. When this operation has begun, if the caterpillar be 

 attentively watched, it will be seen that every half-minute or so 

 he gives a slight upward jerk of the head, followed by an 

 undulating movement passing down the body to the tail. After 

 this has gone on for about a couple of hours, it will be noticeable 

 that the skin, especially the upper part of it, is getting so thin 

 that the yellow colour of the chrysalis can be distinctly seen 

 through it, whilst a wrinkled mass of the integument has 

 collected round the point where the tail is attached. About this 

 time the skin begins to split on the second segment. The move- 

 ments of the body now go on almost without intermission, and 

 the opening rapidly widens, till the split extends down the centre 

 of the back, fi-om the head to a little below the loop. Meanwhile 

 the skin goes on steadily sliding down, and accumulating beneath 

 the tail. The reason the skin does not give way will be seen by 

 examining the shrivelled slough immediately after it is cast off. 



