Page:The Zoologist, 4th series, vol 3 (1899).djvu/475

Rh universal in the Pieridæ, are apparently confined to this group among the Rhopalocera. This fact enables the interesting observation to be made, that where a Pierid mimics an insect belonging to another family, the pigments in the two cases are chemically quite distinct. This is well seen in the genera Leptalis and Mechanitis respectively." The experiments and conclusions of Dr. McNunn and Miss Newbigin in relation to the green pigments in Invertebrates have already been referred to in these pages (ante, p. 430).

The leaf-like Phasmid (cf. ante, p. 303) observed by Mr Belt standing immovable among a host of foraging ants, many of which ran over its legs without discovery that food was within their reach. (This may also be taken as an illustration of "Active Mimicry," referred to subsequently.)

The larvæ of Geometrid Moths, which so resemble the twigs on which they rest as to deceive their enemies. Rösel's gardener, mistaking one of these caterpillars for a dead twig, started back in great alarm when, upon attempting to break it off, he found it was a living animal. Burmeister was similarly deceived by the larva of ''Ph. quercinaria,'' Borkh. (Eunomus erosaria, Tr.), "mistaking it for a small dry twig upon wishing to break off a small twig of oak." Mr. Jenner Weir writes:—"After being thirty years an entomologist, I was deceived myself, and took out my pruning-scissors to cut from a plum-tree a spur which I thought I had overlooked. This turned out to be the larva of a Geometer two inches long. I showed it to several members of my family, and defined a space of four inches in which it was to be seen, but none of them could perceive that it was a caterpillar."

In plants, Matricaria chamomilla is considered a mimic of the true Chamomile, which from its bitterness is not eaten by quadru-