368 Mr. 'Ponlton 8 fiu'tlier experiments upon 



and the question arises as to whether these or the hirvse 

 without food gave the more normal results. 



Assuming that the power of resembling surrounding 

 surfaces is normal to the species (and we are justified in 

 assuming this), the extent of resemblance becomes some 

 test of the normal condition, including duration of the 

 preparatory stages, in which the resemblance is brought 

 about. The pupal colours are tabulated at the end of 

 the last analysis (pp. 366, 367), which distinctly shows 

 that the number of exceptions is far greater among the 

 pupte in the receptacles without food, the larvae of which 

 passed through the longer preparatory stages. It becomes 

 probable that some of the more irritable larvse, which are 

 so disturbed by the shock of capture that they refuse to 

 feed, do not pass into a normal preparatory period, so 

 far as Stages I. and II. are concerned, and, inasmuch as 

 Stage II. is in this species the chief time of susceptibility, 

 frequently produce pupae which are abnormal in that 

 they are exceptions to the usual resemblance to sur- 

 roundings. If this be so, the normal susceptibility of 

 the species must be far higher than that indicated by the 

 results of my previous paper, in which the larvae were 

 generally treated as in the receptacles without food; and 

 Stages I. and II. must be far shorter. 



On the other hand, it must be remembered that the 

 batch of 44 larvae were probably the last of a large 

 company, while the 15 provided with food were the last 

 of the batch. If there is any tendency towards the 

 shortening of the stages in the latest larvae, these 15 

 would exhibit the tendency. There is, however, no 

 evidence for the existence of such a tendency, and the 

 fact that pupation occurred far later in certain larvae 

 without food than in any of those i)rovided with it, 

 seems to indicate that we are dealing with an abnormal 

 protraction of the preparatory period, — the larvae which 

 were the first to leave the food being much the last to 

 pupate. 



Upon the whole, it is probable that the preparatory 

 stages of the 15 larvae are about normal, and that 

 Stages I. and II. are made too long in my previous 

 paper. It is true that the early stages are hurried on by 

 the shock of capture, but they appear to be far from 

 hurried through. 



Stage III. does not seem to be affected by disturbance 



