Thereva foxi Cole, 1923
Diagnostic description:
Thereva foxi is distinguished from similar sympatric species by the dark brown maculation narrowly bordering the wing veins. Males of T. foxi have dark brown distal and acrostichal thoracic tomentum, predominantly shining abdominal tergites, and a broad ventral apodeme; males of T. foxi is distinguished from T. brunnea by the narrow inner gonocoxal process. Females of T. foxi have a slightly projected frons with the lateral and ventral margin of the central shining area convex and the ventral margin distinct.
Size:
9.5-15 mm
Distribution:
Western North America (Yukon south to Oregon and southern Colorado).