We thus see that also in the genus _Pterogon_ the marking of the caterpillars commences with a longitudinal line formed from the subdorsal; an infra-spiracular or also a supra-spiracular line (_Gorgoniades_) being added. A latticed marking is developed from the linear marking by the breaking up of the latter into spots or small patches, which finally (in _Œnotheræ_) become completely independent, their connection with the linear marking being no longer directly perceptible. THE GENUS SPHINX, LINN. Of this genus (in the narrow sense employed by Gray) I have only been able, in spite of all trouble, to obtain fertile eggs of one species. The females cannot be induced to lay in confinement, and eggs can only be obtained by chance. I long searched in vain the literature of this subject for some account of the young stages of these caterpillars, and at length found, in a note to Rösel’s work, an observation of Kleemann’s on the young forms of _Sphinx Ligustri_, which, although far from complete, throws light on certain points. From a female of _S. Ligustri_ Kleemann obtained 400 fertile eggs. The caterpillars on emerging are “at first entirely light yellowish-green, but become greener after feeding on the fresh leaves;” the horn is also at first light green, and then becomes “darker.” The young larvæ spin webs, by which they fasten themselves to the leaves of their food-plant (this, so far as I know, has not been observed in any species of _Sphingidæ_). They moult four times, the border round the head and the purple stripes appearing after the third moult, these stripes “having previously been entirely white.” The ecdyses follow at intervals of about six days, increasing to about ten days after the fourth moult.[118] From this short account we gather that in the third stage the marking consists of seven oblique white stripes, which acquire coloured edges in the fourth stage, a fact which I have myself frequently observed. On the most important point Kleemann’s observations unfortunately give no information--the presence or absence of a subdorsal line in the youngest stages. That he does not mention this character, can in no way be considered as a proof of its actual absence. I am rather inclined to believe that it is present in the first, and perhaps also in the second stage. There occur, however, species of the genus _Sphinx_ (_sensû strictiori_) which possess a subdorsal line when young, as I think may be certainly inferred from the fact that the remains of such a line are present in the adult larva of _S. Convolvuli_.