It is found in all of Europe, east to southern Siberia,[1] as well as the north-eastern parts of North America, where it might be an introduced species.

Forewings are dark purplish-grey, mixed with black, with some whitish scales; a yellow subdorsal spot in the middle, and a smaller one in disc posteriorly; an ill-defined ochreous-white tornal spot, and another on costa at 3/4.

Pnigalio gyamiensis is a larval-pupal ectoparasitoid of Chrysoesthia sexguttella.

The female of P. gyamiensis lays a single egg on the skin of the host larva or nearby it, without any significant preference for a particular variant.

The presence of long hairs on its body provides the newly hatched first larval instar with high mobility.