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INTRODUCTION.
Each of these three sections is then divided into tribes, according to characters derived from the caterpillars and the perfect insect. Among those furnished by the latter, the most important are considered to be the number of ambulatory legs and the form of the palpi. The genera are characterised by the form of the caterpillar and chrysalis, by the dispositions of the nervures of the wings, the form of the antennæ, legs, palpi, thorax, &c. of the perfect insect.
