Page:The Zoologist, 3rd series, vol 2 (1878).djvu/164

142 colour, and in the second or divergiug form it was ochreous-browu, or in some specimens whitish ochreous.

Sir John Lubbock read a paper "On the Colouring of British Caterpillars." Starting from the principles laid down by Darwin, Wallace, and others, that dull-coloured, green, and smooth-skinned caterpillars are eaten by birds, &c, while spiny, hairy, and brightly-coloured species are rejected, the author proceeded to show by a statistical method of tabulation that no hairy caterpillars are green, while, on the other hand, a large majority of black and brightly-coloured caterpillars are hairy.

Mr. Jenner Weir expressed his warm approval of the method by which Sir John Lubbock had treated the subject, and remarked that the results obtained forcibly illustrated the antagonism between green coloration and hairy protection. He further stated that during the past summer he had seen the larvae of Euchelia Jacobeæ in great profusion on Senecio, which plant had been completely stripped of its leaves over a large area of the New Forest. The great abundance of this caterpillar he regarded as a natural experiment on a large scale illustrating the truth of the doctrine advocated.

Mr. J.W. Douglas asked whether the bright colours of the caterpillars actually frightened away birds. He remarked that it was well known that the Shrikes impaled brightly-coloured and hairy insects, such as bees.

Sir John Lubbock replied that the bright coloration or hairy covering of a caterpillar acted simply as a warning that the species was inedible. It was clearly an advantage to a distasteful species to be recognized as such before being pecked at by a bird, and not after being seized, in which case the larva, although perhaps not killed at the time, would in all probability ultimately die of the wounds indicted. Thus by the action of Natural Selection had bright colours and hairs become associated with distasteful qualities.

Mr. M'Lachlan stated that in 1865 (Trans. Ent. Soc, ser. 3, vol. ii.) he had called attention to the fact that some flower-frequenting caterpillars were of the same colours as the flowers on which they fed. He remarked that this was especially the case with the genus Eupithecia. Mr. M'Lachlan also called attention to the fact that the larvae of many Sphingidæ, such as Acherontia Atropos were known to present two distinct forms or coloured varieties.

Mr. Butler remarked that he could fully endorse Sir John Lubbock's view of the function of the oblique stripes on the sides of Sphinx larvæ—that these markings were intended to represent the shadow-lines cast by leaves. He mentioned that he had recently had an opportunity of observing Sphinx ligustri under conditions most favourable to this deception. Mr. Butler further remarked that many of the exotic larvae belonging to the genera Sphinx and Smerinthus were dimorphic. With reference to colour