Lithostege Hübner [1825] 1816

Sh, Hossein Rajaei, Stüning, Dieter & Viidalepp, Jaan, 2011, A review of the species of Lithostege Hübner, [1825] 1816 (Lepidoptera: Geometridae, Larentiinae), occurring in Iran and adjacent countries, with description of two new species from Iran and Pakistan, Zootaxa 3105, pp. 1-46 : 3

Lithostege Hübner [1825] 1816

Type species: Geometra griseata Denis & Schiffermüller, 1775 . Type locality: Austria, Vienna district.

Generic description. Small to medium-sized moths, wingspan ranging from 16 to 35 mm. Forewings elongate, apex acutely angled or slightly falcate, termen oblique, tornus shallowly and evenly rounded. Hindwings oval, short and narrow, moderately or strongly reduced in size. Venation: Forewing with two areoles. The anal vein of hindwings in male short and hidden in an elongate, basal pocket in males, pocket absent and vein longer in females. Frons moderately protruding, surrounded by a sharp ridge; vertex with distinct lateral chaetosemata, both connected by a transverse band of setae; palps slightly or moderately exceeding frons, covered with enlarged, sometimes elongated, lamellate scales. Antennae: very shortly and homogenously ciliated in males, filiform in females. Haustellum well developed. Femora of forelegs in both sexes strongly thickened, fore-tibia extremely short, with a massive distal, forked projection, consisting of a long internal and a much shorter external tooth. The longer tooth is often as long or longer as the tibia. Epiphysis present, but very small. Middle tibia with one, hind tibia with two pairs of rather delicate spurs. Last abdominal tergite very large and strongly sclerotized, its posterior margin evenly rounded, with a small central incision or shaped like a buckle or snout in some species. In the male genitalia, a process arising from the basal centre of valva (termed “harpe” in the following species account) is distinctive, in most species basally extended into an arched or curved, distally spined dorsal arm, running along the valve costa towards the apex (absent in L. amoenata group, see species account). In some species, additional ornamentation like costal or saccular processes is present. In most species the bursa copulatrix is internally spined and extended anteriorly to a small, membranous diverticulum (not present in L. excelsata and L. distinctata ).