[143] [The same applies to _Pseudoterpna Cytisaria_, also feeding on broom at the same time of the year. The most striking cases of adaptive resemblance brought about by longitudinal stripes are to be found among fir and pine feeders, species belonging to the most diverse families (_Hyloicus Pinastri_, _Trachea Piniperda_, _Fidonia Piniaria_, &c., &c.) all being most admirably concealed among the needle-shaped leaves. R.M.] [144] The geographical distribution of the dark form indicates that in the case of this species also, the form referred to is replacing the yellow (green) variety. Whilst in the middle of Europe (Germany, France, Hungary) the dark form is extremely rare, in the south of Spain this variety, as I learn from Dr. Noll, is almost as common as the yellow one. I hear also from Dr. Staudinger that in South Africa (Port Natal) the dark form is somewhat the commoner, although the golden-yellow and, more rarely, the green varieties, occur there. I have seen a caterpillar and several moths from Port Natal, and these all agree exactly with ours. The displacement of the green (yellow) form by the dark soil-adapted variety, appears therefore to proceed more rapidly in a warm than in a temperate climate. [Eng. ed. Dr. Noll writes to me from Frankfort that the caterpillar of _Acherontia Atropos_ in the south of Spain does not, as with us, conceal itself by day in the earth, but on the stems underneath the leaves. “At Cadiz, on the hot, sandy shore, _Solanum violaceum_ grows to a height of three feet, and on a single plant I often found more than a dozen _Atropos_ larvæ resting with the head retracted. It can easily be understood why the lateral stripes are blue when one has seen the south European _Solaneæ_, on which this larva is at home. _Solanum violaceum_ is scarcely green: violet tints alternate with brown, green, and yellow over the whole plant, and between these appear the yellow-anthered flowers, and golden-yellow berries of the size of a greengage. Thus it happens that the numerous thorns, an inch long, between which the caterpillar rests on the stem, pass from violet into shades of blue, red, green, and yellow.”] [145] [For Mr. J. P. Mansel Weale’s remarks on the habits of certain ocellated S. African Sphinx-larvæ see note 129, p. 290. R.M.] [146] [Some experiments with the caterpillar of _C. Elpenor_, confirming these results, have been made by Lady Verney. See “Good Words,” Dec. 1877, p. 838. R.M.] [147] [The eye-spots on _Ch. Nerii_ have thus been supposed by some observers to be imitations of the flowers of the periwinkle, one of its food-plants. See, for instance, Sir John Lubbock’s “Scientific Lectures,” p. 51. R.M.] [148] “On Insects and Insectivorous Birds,” Trans. Ent. Soc. 1869, p. 21. [149] _Ibid._, p. 27. [150] [Messrs. Weir and Butler inform me that they have not experimented with Sphinx-larvæ. R.M.]