The immature stages of Chrysomelidae fall into five natural groups—Tricho-stomata, Cyclica, Eupoda, Camptosomata, and Cryptostomata, which coincide with the recognized divisions of imagines.

An account is given of the biology and external morphology of the early stages of thirty-five species.

The principal systematic characters are the chatotaxy, mouth-parts, and number of ocelli in the larva, and the chaetotaxy in the pupa.

The larval mouth-parts are remarkably constant, but the numbers and disposition of the primary setae afford characters of taxonomic importpnce.

The hypothetical segment possesses sixteen pairs of setæ, arranged into two transverse rows.

The Trichostomata are considered to be the least modified forms, and of the Chrysomelince the Phœdonina are the most generalized. The Eupoda, Campto-somata, and Cryptostomata are somewhat divergent forms which appear to have developed along their own paths of specialization.