Genus Lithostege Hübner, 1825

Type species: Geometra griseata Denis & Schiffermüller, 1775.

Diagnosis. The genus can be diagnosed by the following synapomorphic characters (Rajaei et al., 2011; Rajaei & Stüning, 2013; Rajaei et al., 2019): the forewing is slightly elongated and features two areoles in its venation. The hindwing is oval, narrow and reduced in size, with a shorter anal vein in males and a longer one in females. The foreleg has a significantly thickened femur; the tibia of the foreleg is extremely short and ends distally with a massive, forked projection that includes a longer internal and a shorter external tooth (see Rajaei & Stüning, 2013: fig. 2). Additionally, the foreleg’s epiphysis is small; the midtibia has one pair of spurs and the hind tibia has two pairs of spurs. The male genitalia of most species feature a harpe, a process arising from the basal centre of valva, which is divided into the basal part and a dorsal arm. The female genitalia of most species possess a membranous diverticulum attached to the corpus bursae.