264 MR. E. B. POULON ON THE PROTECTIVE [Mar. 1, 



in the former lias been previously alluded to. A friend has raised 

 the ol)jectiou tliat the moth imitates a piece of twig cut cleanly at 

 both ends, an object which cannot be found in nature unassisted by 

 art. The reply of course is that the pur[)le and grey colour of the 

 sides of the suggested cylinder, together with its pale ochreous ends 

 — the one appearing to be cut transversely, the other obliquely across — 

 present a most perfect resemblance to wood, with that particular 

 condition of texture induced by decay, in which alone the tissue will 

 break shortly and sharply as if cut, ou the application of slight 

 pressure or the force of an insignificant blow. In coitu the stick- 

 like appearance is admirably preserved, the two insects looking like 

 a single twig (Newman). It was clear from the energetic and 

 instantaneous attacks made on these moths, that tlie Lizards expected 

 them to be palatable and that the unpleasant quality is incidental 

 and useless. It was very interesting to observe that the coutinuity 

 of the unpleasant properties through the different stages in this 

 species is accompanied by a gradual lessening in their powers. The 

 larva was certainly disliked far more than the other stages, and the 

 pupa seemed to be more neglected than the imago, the latter being 

 eaten in large numbers, although often after preliminary tasting and 

 temporary rejection. This fact also favours the explanation given 

 above of the origin and meaning of the unpleasant qualities in the 

 two terminal stages. 



In the case of O. antiqua, we have a most inconspicuous insect 

 with the same unpleasant taste. Hei'e also the same explanation 

 probably holds good as far as the origin of the qualities is concerned, 

 for we have previously seen that its most brightly-coloured and freely 

 exposed larva was disregarded by all the birds. In this case I do 

 not yet feel certain that the property may not be of some value to 

 the female images ; for it would be impossible to find a more helpless 

 insect, without even the power of attempting to escape by walking. 

 More observations are greatly needed, and it would be especially 

 interesting to ascertain whether the quickly-flyirig males are equally 

 disliked as food. 



The pupa of P. bucepliala has been already alluded to. Confir- 

 mation is, I think, needed of Newman's statement that fowls eat this 

 pupa freely, for the dislike of the Lizards was extremely marked, and 

 as a rule these animals are less delicate than birds. The pupse of V. io 

 and F. urticce possess the highest form of protective resemblance ; 

 and here, again, Jenner Weir's observation, I think, should be repeated, 

 as the Lizards acted so very differently with the latter species. Is it 

 quite certain that the birds were aware of the presence of these 

 generally motionless puj)8e in Jenner Weir's experiments ? 



The consideration of the fourth subdivision of the list, including 

 species of Arthropoda other than the Lepidoptera, enforces very 

 strongly the conclusions of the rest of this paper, — that defensive 

 habits and structures may exist in almost any kind of combination, 

 so that we find plenty of instances of the co-existence of unpleasant 

 attributes with protective resemblance, as well as with a " warning " 

 appearance. 



