Anyway, last year I found this species to be common near Bao Loc at the type locality in early June. But a few days later I bumped into another small Heliogomphus in Gia Lai Province. Outward it was a little different in coloration. Notably, the superior appendages were more extensively white and S7 had a distinct anterior pale yellow ring. With differences between Heliogomphus species often slight, I thought it might be a different species, but checking it under the microscope I cannot but conclude the appendages and vesica spermalis are identical. If so, the slightly different coloration is likely nothing but a geographical variation. I concluded that the Gia Lai specimen is also H. chaoi. That species is therefore much more widespread than previously thought.
|Heliogomphus chaoi in Bao Loc. Note it only has on S7 a pale yellow line along the dorsal carina and a lateral basal spot.|
|Another male at the same location|
|And the appendages in dorsal view|
|Heliogomphus chaoi at Gia Lai. Note the small yellow dorsal spot on S8 and the large anterior yellow ring on S7. But structurally it is not different.|
|The appendages in dorsal view, the white more extensive|