[2][3] Howes used a specimen collected by Charles E. Clarke in March at Flagstaff Hill in Dunedin and named the species in his honour.

[2][3] George Hudson discussed and illustrated this species in his 1928 book The Butterflies and Moths of New Zealand.

Termen distinctly edged with a thin black line, interrupted by yellow dots at the ends of the veins.

[8] H. clarkei is considered extinct at its type locality of Flagstaff Hill.

[4] This moth is classified under the New Zealand Threat Classification system as being "At Risk, Declining".