Mr. R. Meldola on Evolution. 159 
that “ they hang loosely about shrubs in the forest, and have 
the extraordinary habit of stretching out their legs unsymme- 
trically so as to render the deception more complete.” Fritz 
Miiller supplies the following analogous instances :—“ The 
caterpillars of some Papiliones resemble fresh excrements of a 
bird; these caterpillars always rest on the upper surfaces of the 
leaves on which they feed, while those of some other Papiliones 
(Nephalion, Polydamas), which are not protected by some such 
resemblance, always hide themselves on the dower surfaces of 
the leaves.”’ 
Even among our own insects hundreds of such cases might 
be noted. Thus the weevils, which resemble pellets of earth, 
tuck in their legs and feign death when alarmed, and the 
stick-like geometer larve erect themselves stiffly from the 
twigs on which they rest. Cucullia chamomille and Galeria 
cerella both resemble broken splinters of wood when at rest; 
and I have seen these moths at the extreme ends of pointed 
palings, where they had erected themselves at an angle to the 
wood, making the resemblance to a broken-off splinter remark- 
ably deceptive. Calocampa vetusta is very like a piece of 
broken stick when its wings are closed; and this moth has 
been seen hanging to a twig by one leg. fasteropacha quer- 
cifolia, which, when at rest, resembles a withered leaf, has been 
seen in a similar attitude. Ctlix spinula is well known to 
resemble a piece of bird-excrement; and I have often seen 
- this moth at rest by day, fully exposed to view, on the upper 
surfaces of leaves. 
It is interesting to observe how, in many cases, natural 
selection has probably taken advantage of characters originally 
acquired for some other purpose. Thus the common Antho- 
charts cardamines of this country has been shown by Mr. T, 
W. Wood to rest at night on the heads of umbelliferous 
plants, where the green marblings on the underside of the hind 
wings of the butterfly cause the latter to bear a very exact 
resemblance to the flower-head. Now, as this style of mar- 
bling is common to many butterflies of the genus in various 
parts of the world, it cannot be assumed that this character 
has been specially acquired to adapt the insects to umbel- 
liferous flower-heads. It is quite as probable, in the case of 
A. cardamines, that the habit of the butterfly has been adapted 
to its particular mode of coloration, natural selection after- 
wards perfecting the resemblance. A similar instance is 
offered by Lithosta caniola, the larva of which feeds on Tri- 
folium repens, and is stated to occur on stony ground which 
abounds with a species of small shell, probably a Helix? 
When alarmed the larva rolls itself into a ring and falls off 
