Idaea poecilocrossa is a moth of the family Geometridae.

The forewings are narrow with a very long cell; whitish; easily recognizable by its thick sinuous postmedian line placed close to termen and its violet-grey subterminal shading, brown costal edge and fringe.

The cell dot is black, median line nearly straight.

The hindwings are distally similar to the forewings.

This Sterrhinae moth related article is a stub.