none The external morphology and duration of the larval instars of Alphidium ervi Haliday are reported. Both light microscopy and scanning electron microscopy were used in this study. The 1st instar is mandibulate-caudate, with sickle-shaped mandibles. The 2nd instar is hymenopteriform and amandibulate, whereas the 3rd instar has well developed mandibles. This research supports the opinion that only 3 larval instars occur in the Aphidiinae.