Hyloicus caligineus subsp. sinicus
Differs from Hyloicus caligineus caligineus in having:body and wings paler, more grey-brown (Hyloicus caligineus brunnescens is intermediate); hindwing with veins Rs and M1 shorter stalked; antenna with scaling white, with a few brown scales on the middle segments; mesothoracic tegulae with brown borders faint, vestigial in the female; forewing upperside with discal streaks faint or absent.
Male genitalia: Similar to Hyloicus caligineus caligineus, but:gnathos less obviously sinuate, the lobes much shorter; valve shorter, more rounded apically; harpe with processes shorter, the dorsal one not curved dorsad apically, the ventral one much narrower; phallus with apical lobe much shorter even than in Sphinx pinastri, more similar to that of Hyloicus oberthueri.
Female genitalia: Ostial plate with lobe more deeply sinuate than in Hyloicus caligineus caligineus.