Helicomastax, a new genus of Central American eumastacid grasshoppers

Abstract

Abstract Helicomastax n. gen. is externally almost identical with Homeomastax Descamps 1979, but has radically different genital structures. In the male the ectophallic sclerites give rise on their anterior medial surface to a pair of chitinous filaments. These enter the spermatophore sac dorsally, run in a circular course within the sac and emerge from its opening ventrally and posteriorly as two fine whip-like projections, which extend dorsally above the ectophallic sclerites. The complex of spermatophore sac, endophallic plate and ectophallic sclerites, forms a sclerotized capsule; the posterior extremities of the ectophallic plate are not inserted into the ectophallic membrane, as in other eumastacine genera, but are free and project to the exterior. The spermathecal duct of the female is longer and more convoluted than in other eumastacine genera, presumably in association with the filaments of the male, which are hypothesized to be inserted into the duct during copulation. The genus is represented b...