Pelecorhynchus olivei is notable for the presence of three large white spots on each of the three main abdominal tergites, giving an immediately distinctive and visible medial row of spots between the wings when the fly is at rest. The thorax dorsally is brownish and adorned with a medial whitish triangle in front of the scutellum, along with a near entire pair of longitudinal whitish stripes either side. The wings are spotted and the abdominal tergite suture hairing golden. On account of the well formed pale abdominal spots this species cannot be confused with any other described species. Bodylength around 12.5 mm.