Ambulyx substrigilis: Resembling Ambulyx liturata in having the basal patch of the hindwing upperside often pale tawny and not conspicuous, but there is more grey on the forewing of the male (as in Ambulyx sericeipennis); the basal patch if the hindwing is less sharply defined in both sexes; forewing upperside usually lacks the sub-basal costal patch, but sometimes it is nearly as large as the spot near the anal margin. The underside of the body, palpi and wings and the upperside of the hindwing is deep orange fulvous. Ambulyx substrigilis substrigilis comes in two forms, a pale, bright tawny-ochraceous form with a bright orange underside, and a darker, drab form with the markings of the hindwing upperside smaller. Diagnosis from https://tpittaway.tripod.com/china/a_sub.htm.