Abstract
The immature stages (egg, mature larva and pupa) of Squamapion atomarium (Kirby, 1808), as well as its development cycle and the phenology of its developmental stages, are described for the first time. The larva and pupa of S. atomarium have typical morphological features of the subfamily Apioninae. Morphological data on the immature stages were compared with the only fully described Squamapion species, S. elongatum (Germar, 1817). The larvae of the two species differ in body size and shape, head shape, setae length, the chaetotaxy of the mouthparts, and individual types of setae on the pronotum and thorax. In the case of the pupa, there are also differences in body size and in the type of setae and chaetotaxy of the head, pronotum, metanotum and abdomen.