U4 LEPIDOPTERA INDICA. 



tlie sombre markings in this group are instance? of protective resemblance, the under- 

 side of the hindwings being marbled or mottled with darker and lighter colours, in 

 such a way as to render the insect very difficult to see when alighted, for instance, 

 upon a gray rock. That this is its purpose, is indicated, not only by the invariable 

 habit of insects of this subfamily to alight with closed wings, showing only their 

 under surface, but their very common trick of immediately dropping the front wings 

 into concealment between the hinder pair, and also of tipping over to one side and 

 resting in a half reclining posture, the gray wing against the gray rock. 



" The caterpillars may be readily recognized by the peculiar bifurcation of the 

 terminal segment of the body ; they are almost invariably clothed only with a 

 short but coarse pubescence arising from jjapillae so numerous as to give a shagreened 

 appearance to the skin, and longitudinally striped with continuous or broken bands 

 of colour. Mr. Distant rightly considers this a form of protective coloui'ing, and even 

 looks upon the foi'ked tail as in some measure protective, and on type of larva as a 

 ' very primitive form.' He remarks (Rhopalocera Malayana, p. 37) that ' they are 

 almost all feeders on various grasses, to which their green coloration and markings 

 assimilate them, thus affording a good example of " protective coloration." ' In an 

 evolutionary sense there are also ample grounds for considering them as exhibiting a 

 very primitive form. Dr. Weissmann (' Studies in the Theory of Descent,' Engl, 

 edit.) has made the most profound and philosophical study of larval characters, jjrinci- 

 pally as found in the SphingidcB, a family which strongly exhibits more or less 

 specialized larval markings. He considers the oldest Sphinx larvse as being without 

 markings and probably protected only by adaptive coloration and a large caudal 

 horn, &c. It is at least probable that the bifid tails of the Satyrince Fulfil an analo- 

 gous protective function with this caudal horn in the Sphingidce, or with the forked 

 horn at the tails of the larvee of some genera of moths. With the next stage of 

 Sphingid evolution, where the larvse have become longitudinally striped, we may 

 almost apply Dr. Weissmann's very words to the Satyrince : — ' The caterpillars thus 

 marked must have been best hidden on those plants in which an arrangement of 

 parallel linear parts predominated ; and we may venture to suppose that at tliis period 

 most of the larv^ of the Sphingidas lived on or among such plants (grasses).' 



"The caterpillars eat slowly and are vfery long in attaining maturity j and as 

 the egg and chrysalis states are usually longer than common, the species of this 

 group are almost without exception single brooded,* and, in the genus OEneis, some 

 species are supposed to take two years to complete the cycle of growth. So far as 

 is known, the larvte feed only on grasses and sedges (the only exception known to 

 me is the European Gcenonymi)lia Hphon, the caterpillar of which is said by Merrin to 

 feed on Rhynchospora, one of the Cyperacece). It is probable that the larvao of 

 * See subsequent remarks on " Seasonal Dimorphism " in tliis subfamily. 



