markings and attitudes of lepidopterous larva. 315 



former attitude the larva nearly always clings to the 

 leaf on which it is feeding, and does not return to the 

 twig in the intervals of rest (as during the succeeding 

 stages). The great feature of the attitude is the 

 remarkable bend in the 3rd thoracic segment, and the 

 intensely exaggerated effect produced by the 3rd pair of 

 thoracic legs j^rojectingfrom their prominent ridge. There 

 is also a bend (in the opposite direction, dorsally con- 

 cave) in the 2nd abdominal segment, and another 

 (ventrally concave) between the 4th and 5th, pointed by 

 the pair of dorsal tubercles on each of these segments. 

 The larva is supported by a thread of silk in the pro- 

 tective attitude. When the thread is cut in two the 

 larva falls into another position, showing that there is 

 considerable tension on the thread. In this second 

 position it remains steady for some time, but eventually 

 the first attitude is again assumed, usually after the 

 appearance of the lateral movements. When a larva is 

 disturbed it is most remarkably passive, thus carrying 

 out its resemblance to immovable objects ; but if the 

 disturbance be increased the lateral movements begin. 



Fourth and Fifth Stages. — The colours and markings 

 of the last two stages are quite similar to those of the 

 third in nearly all cases (see fig. 18, natural size, Plate 

 VII.; end of fifth stage). Occasionally the white band 

 on the 2nd abdominal segment seems to be absent, and 

 sometimes it is concealed beneath the reflected hinder 

 part of the 1st abdominal segment. The attitude is, 

 however, quite different from that assumed in the third 

 stage, and is of the type most usual among Geometers, 

 protection being gained by resemblance to a twig. The 

 head and first two thoracic segments are bent back, as 

 in the third stage, but not to an equal extent, and the 3rd 

 pair of thoracic legs are held as before, and the support- 

 ing thread often passes between them. The bend is, as 

 before, rendered more effective by the swollen sides of 

 the 2nd thoracic segment. The rest of the body is held 

 straight, especially the cylindrical 1st, 2nd, and 3rd 

 abdominal segments. The resemblance to a twig, with 

 a projection on one side of the extremity, is very 

 striking. The projection is formed by the head and 

 first two thoracic segments, for by position, shape, and 

 colouring the line of the body is continued into the ridge 

 on the 3rd thoracic segment and the 3rd pair of thoracic 

 legs, which appear as the real termination of the object. 



