PROCEEDINGS OF SCIENTIFIC SOCIETIES. 309 
Mr. M‘Lachlan stated that the bright coloration of larvae was no pro- 
tection from the attacks of ichneumons. He also remarked that the larva 
of Diloba ceruleocephala was found feeding sometimes on sloe and sometimes 
on laurel, and raised the question whether specimens found on the latter 
plant would be poisonous, and those on the former innocuous. 
Mr. Meldola stated that, with regard to the chemical aspect of the question, 
he believed it possible for a poisonous substace derived from a food-plant to 
permeate the tissues of a caterpillar without undergoing any change. The 
evidence upon which this statement rested was to be found in the fact that 
the colouring matters of some plants had-been found by means of the 
spectroscope in the tissues of larvee which fed upon them in an unaltered 
condition. If colouring matters escape the digestive processes unaltered it 
is probable that organic poisons would do the same. On the other hand, 
it is well known that larvee feeding on non-poisonous plants may elaborate 
poisons by chemico-physiological processes. The larva of Liparis aurifiua, 
which feeds upon hawthorn, sloe, apple, oak, &c., and which possesses the 
well-known property of “ urticating,” was adduced as an example. 
Mr. M‘Lachlan remarked that it was now generally admitted that the 
urticating property was due to mechanical irritation, the numerous brittle 
hairs of the larva entering the skin. 
Mr. Dunning and Mr. Waterhouse raised the question whether the hairs 
thus penetrating the skin might not possess some poisonous quality. 
Mr. Meldola further remarked that he had observed that certain dis- 
tasteful species of Lepidoptera preserved their disagreeable qualities after 
death, in proof of which he exhibited some butterflies found among an old 
collection of Indian insects, the greater part of which had been demolished 
by mites. The surviving specimens were all of protected species, viz. four 
of a Huplea, one of Danais plexippus, and one of Papilio Pammon. Euplea 
and Danais,were well known to be protected genera, since they serve for 
models of mimetic resemblance. \\ith regard to Papilio Pammon, Mr. 
Meldola stated that in his belief it was in some way distasteful, as he had 
seen it in swarms in the island of Nancowry, Nicobar Islands, in April, 
1875. 
Mr. M‘Lachlan stated as a contrary fact that Cantharides is particularly 
subject to the attacks of beetles. 
With regard to the means by which bright coloration might have become 
associated with poisonous qualities in a larva, Mr. Meldola reminded the 
Society of the experiments of Messrs. Jenner Weir and A. G. Butler, com- 
municated to them in 1869. These gentlemen had proved that brightly- 
coloured, hairy and spiny caterpillars were generally distasteful, while dull 
species were devoured. Mr. Wallace was of opinion that the observed 
correlation between bright coloration, &c., and distastefulness was brought 
about by means of Natural Selection. Mr. Meldola quoted the following 
