Abstract: Morphology of immature stages of the citrus borer (Agrilus auriventris Saunders) was studied in details both in field and in the laboratory using Leica MZ 16A stereo microscope with Leica IM 1000 system. The results showed that eggs were creamy white when first laid, but they became yellow and wizened with age. Before hatching, white and waxen outer layer and yellow inner layer were derived from the chorion; during hatching, the larva bored directly into phloem from the bottom part of the egg adhered to the bark with sawdust-like dejecta in the chorion. The shape of larval urogomphi and the width of peristoma varied with increase of instar, and the last-instar larva made a elliptic cell in the xylem with its body folded from head to tail with a ratio of 3∶7. A prepupal stage appeared before pupation; when the pupae aged, their body turned yellow and compound eyes became rufous from creamy white, and then, a status with yellow body, rufous compound eyes and black mouthpart appeared. Before eclosion, the whole pupa became black; during eclosion, exuvia cracked as the expand the adult body. After the fore wings became black and the dorsal aspect of the abdomen blue, the adult gained all adult characters. This study further confirmed that the larvae of this beetle had 5 instars.

Key words: Agrilus auriventris, immature stages, morphology, chorion, hatch, pupation, eclosion