ABSTRACT
Abdomen with five visible sterna; first two visible sterna fused, suture only partially visible in some groups. Male genitalia with aedeagus inverted (Abdullah 1974, Lawrence 1982).
Larva: Only three genera have had their larvae thoroughly described: Escalerosia from Japan (Hayashi 1972); Megaxenus from Australasia (Lawrence et al. 1990); and Vanonus from Mexico (Yanega and Leschen 1994). Larvae reach up to 6 mm; body elongate, subcylindrical to flattened; whitish except for darkened mouthparts and urogomphi; body with scattered, elongate hairs. Head transverse and flattened, exserted from prothorax, narrower than prothorax; epicranial suture with stem short or lacking, frontal arms abruptly divergent at apical third toward antennae; lacking median endocarina; labrum free, lacking frontoclypeal suture (present in Vanonus); lacking stemmata; mandibles asymmetrical (nearly symmetrical in Vanonus), left mandible with prominent molar tooth, both with well developed mola and fleshy hyaline lobe at base (lacking in Megaxenus and Vanonus); antennae with sensorium of second segments large, conical; maxillae with 1segmented cardo, simple maxillary mala, and 3-segmented palps; lacking hypostomal rods. Ninth tergite with pair of fixed, upwardly curved urogomphi at apex (lacking in Megaxenus); ninth sternite lacking asperities; anal orifice oriented caudally; spiracles annular (Abdullah 1974, Young 1991).
