markings and attitudes of lejndopterous larva. 329 



the protection is not by resemblance to a twig, but to an irregular 

 fragment upon a leaf, such as the excrement of a bird or a brown 

 piece of leaf. 



Fig. 18, natural size. — The full-grown larva of S. illunaria, seen 

 from the left side, at rest upon a twig. There is no essential 

 difference between the colouring of this stage (fifth) and that of the 

 third (fig. 17), and the intei-vening fourth stage is, of course, similar. 

 Nevertheless, the appearance is very different, and this is entirely 

 due to the attitude. The bend in the 3rd thoracic segment is still 

 very prominent, but it is not so great as in the third stage. The 

 effect is still to prolong the Ime of the body into the ridge on the 

 ventral aspect of the 3rd thoracic segment and the 3rd pair of thoracic 

 legs. The rest of the body is held straight, and the resemblance 

 is to a lateral twig of the branch upon which the larva is resting. 

 The effect of the anterior bend is very peculiar and unlarva-like. 

 The white marks upon the 2nd abdominal segment are nearly 

 always present. The thread which supports the larva in the 

 protective attitude often passes between the 3rd pair of thoracic legs 

 (see figure). The attitude and appearance in the fourth stage is 

 similar to that just described and shown m fig. 18. The ground 

 colour is very variable. 



Fig. 19, natural size. — The larva of Ennomos angiilaria before 

 pupation, seen from the right side. The colours have undergone 

 change, and the larva was taken out of its cocoon to be figured. The 

 adult larva was dark colom-ed and twig-like, but the colours have 

 entirely changed to greenish tints. Thus the larva is inconspicuous 

 against the surrounding leaves, which are fastened together to 

 form its cocoon. This is important, for the loose construction of 

 the latter renders the larva easity visible. 



Fig. 20, natural size. — The pupa of J5J. angularia, seen from the 

 left side. The pupa was nearlj;- ready for the emergence of the 

 imago, for the darkened eyes can be seen through the covering 

 In this form the pupa is bluish green, covered with white pomts. 



Fig. 21, natural size. — The pupa of E. angularia, seen from 

 above. The figure shows the other form of this dimorphic pupa. 

 It is of a brownish-green colour, sprinkled with black dots. Both 

 these forms are well protected in the cocoon, and it is probable 

 that the species is directly benefitted by the dimorphism. 



TRANS. ENT. SOC. LOND. 1885. — PART. 11. (AUG.) 



