Mayfly Species Pentagenia robusta (Robust Burrowing Mayflies)

Eyes slightly larger than in Pentagenia vittigera; thorax and broad dorsal abdominal stripe deeper, shinier blackish brown; broken brown lateral lines on abdominal sternites.

Eyes larger than in Pentagenia vitteriga general appearance more robust. Thoracic notum deep shiny blackish brown; only a narrow lateral yellow margin on prothorax. Pleura tinged with brown, sternum largely brown. Fore tibia and tarsus light brown, darker at joints. No traces of black dots on the fore wing; both longitudinal and cross veins distinctly pale brown. The broad dorsal band on the abdominal tergites is deep shiny black-brown. The abdominal sternites are marked with broken, brown lateral lines, as in Ephemera; sternites 8 and 9 with considerable brown shading. Tails distinctly brown, joinings narrowly pale; forceps tinged with brown. In other respects, similar to vittigera.

This species differs from Pentagenia vittigera as indicated above; the main differences being the lack of black spots in forewing and the pale brown venation; deeper and shinier color of thorax and abdominal dorsum; dark lateral streaks on sternites; tails darker.