Key to the species of Stenopygium Becker 1 Male postpedicel elongate and distinctly narrowed distally, with ventral indentation (Fig. 2); female postpedicel triangular (Fig. 3); mesonotum without gray dorsocentral stripe (Fig. 5); wing mostly brown (Fig. 4); male terminalia with cercus long and narrow, as long as hypopygium (Fig. 6)................................................... S. nubeculum Becker - Male postpedicel without ventral indentation, neither prolonged nor distinctly narrowed distally (Fig. 10); female postpedicel subtriangular with rounded apex (Fig. 11); mesonotum with gray dorsocentral stripe interrupted by dark brown spots at base of dorsocentral bristles (Fig. 13); wing hyaline, with brown spots, mostly evident on anterior half of wing (Fig. 12); male terminalia with cercus short and subtriangular, shorter than hypopygium (Fig. 14)...................... S. punctipennis (Say)

Published as part of Soares, Matheus M. M. & Ale-Rocha, Rosaly, 2020, New records of Stenopygium Becker (Diptera: Dolichopodidae) from the Neotropical Region, and a key to species, pp. 129-134 in Zootaxa 4868 (1) on page 129, DOI: 10.11646/zootaxa.4868.1.7, http://zenodo.org/record/4417397