1	Forewing with postmedial line straight or evenly curved, usually prominent	2
–	Forewing with postmedial line dentate, usually obscure	5
2	Forewing with postmedial line appearing to extend to apex and usually highlighted by yellow line or spots	Argyrostrotis flavistriaria
–	Forewing with postmedial line subapical and without yellow shading	3
3	Forewing with postmedial line curved toward wing base at costa; basal, medial, and terminal areas may be extensively dusted with white scales	Argyrostrotis sylvarum
–	Forewing with postmedial line straight; ground color brown	4
4	Postmedial line complete	Argyrostrotis quadrifilaris
–	Postmedial line incomplete	Argyrostrotis anilis
5	Forewing length 15–17mm; fringe with white scaling	Argyrostrotis erasa
–	Forewing length 10–13 mm; fringe rarely with white scaling and if so, scaling minute	Argyrostrotis deleta