The caterpillars of this genus are very similar in appearance, and all
possess extremely simple markings. The occurrence of numerous stages
of development of these markings is thus excluded, and the study of the
ontogeny therefore promised to furnish less information concerning the
phyletic development of the genus than in the case of the preceding
genera. This investigation has nevertheless also yielded interesting
results, and the facts here recorded will be found of value in likewise
throwing light on the causes which have produced the markings of
caterpillars.
I shall commence, as in former cases, with the developmental history.
I have easily been able to obtain fertile eggs of all the species of
_Smerinthus_ known to me. Impregnated females laid large numbers of
eggs in confinement, and also bred females of the commoner species can
readily be made to copulate, when pinned, and exposed in a suitable
place in the open air. A male soon appears under these circumstances,
and copulation is effected as readily as though the insect were not
fastened in the way indicated.