In this fourth stage the larva of _D. Hippophaës_ is of a lighter green (Fig. 58), the subdorsal yellowish with sharp boundaries, and the infra-spiracular line pure white, as in the next stage. The shagreening is present, but none of the shagreen-dots are red or reddish, and no trace of a ring-spot can be detected on the subdorsal line with the exception of that on the eleventh segment. In this last position this line is somewhat widened, and a long, diffused, rose-red spot can there be recognized upon it (Fig. 58 A). The black “ground-area” present in the fifth stage is as yet absent, and the spot is not so sharply separated anteriorly from the subdorsal line as it becomes later. From these observations we might venture to expect that in the third stage of _Hippophaës_, the subdorsal line would also be free from this spot on the eleventh segment, and it is possible that in the second stage this line is itself absent. THE GENUS DEILEPHILA: SUMMARY OF FACTS AND CONCLUSIONS. Regarding only the _adult_ larvæ of the species of _Deilephila_, these represent in their five groups, five stages in the phyletic development of the genus; but if we also take into consideration the developmental history, two more stages must be added, viz., that in which the caterpillar possesses no particular marking, as was found to be the case in the first stage of the development of _D. Euphorbiæ_ and _D. Dahlii_; and a second stage with a subdorsal line, but without any ring-spot formations. Seven stages of phyletic development must therefore be distinguished. _Stage 1._--No species with entire absence of marking in the adult form now occurs. _Stage 2._--A subdorsal, accompanied by a spiracular line, extends from the caudal horn to the first segment. This also no longer forms the final stage of the ontogeny, but is, however, undoubtedly retained in the second stage of several species (_D. Vespertilio_, _Livornica_, _Lineata_, and perhaps also _Galii_). _Stage 3._--The subdorsal line bears a ring-spot on the penultimate segment; the other markings as in the last stage. _D. Hippophaës_ only belongs to this stage, a small number of specimens, however, showing a transition to the following stage by the transference of ring-spots from the posterior to the anterior segments. _Stage 4._--Open ring-spots appear on the subdorsal line on all the segments from the eleventh to the first. _D. Zygophylli_ and the North American _D. Lineata_ belong here. _Stage 5._--Closed ring-spots are situated on the subdorsal line. Of the known species, only _D. Livornica_ concludes its development at this phyletic stage. _Stage 6._--A single row of ring-spots replaces the subdorsal line. _D. Galii_, _Vespertilio_, and _Mauritanica_ represent this stage at the conclusion of their ontogeny.[95]