Bioacoustics of Letana

Diagnosis. The genus is of medium size, slender, quite delicate, often parapterous, but brachypterous forms also exist; usually green, rarely colourful species with a bilobate and arcuate sub-genital plate in the male; occiput is convex, fastigium vertices narrow, dorsally sulcate, distally depressed, circa right-angularly inserted with fastigum frontis; antennae thin ( Ingrisch, 1990 ). Pronotum short with disc almost flat, first transverse sulcus sub-interrupted in the middle; second transverse sulcus small, V- or Y-shaped, anterior margin concave, posterior margin straight to convex; tegmina translucent to opaque, with an irregular network of veinlets between the principal veins; branching of radial sector visible before or in the middle of tegmina; stridulatory file arcuate, sub-straight or sinuate, sometimes complex in structure, stridulatory pegs usually dense at the anterior end, larger and distinctly separated in the middle and at posterior end; prosternum obtuse, meso- and meta-sternum sub-lobate; tibial tympana open on both sides; ninth tergite arcuately prolonged behind and more or less covering abdominal apex; the 10th tergite fused with epiproct to a large and highly modified supra-anal plate of varying shape, sub-basally bowed down in 45 0 to 90 0 angles, with or without lateral appendages.