Key to the species of Merulempista from China
1. Forewing with a round spot inside antemedial line (Fig. 4).................................................... 2
- Forewing without spot inside antemedial line............................................................... 3
2. Male flagella with pectination on basal 2/3 of ventral side, costa with a small thorn distally (Fig. 5), posterior margin of antrum serrated in female genitalia (Fig. 7)....................................................... M. pectinata sp. nov.
- Male flagellae without pectination, costa without thorn, posterior margin of antrum smooth in female genitalia (Ren and Li, 2011)................................................................................. M. cyclogramma
3. Distal part of process in costa blunt (Fig. 3).......................................... M. similirubriptera sp. nov.
- Distal part of process in costa pointed..................................................................... 4
4. Costal process triangular, cornuti not reach end of phallus........................................... M. rubriptera
- Costal process digitiform, cornuti reach end of phallus....................................................... 5
5. Distal process of costa obliquely upward, forms an acute angle with valva at outside (Ren and Li, 2011)..................................................................................................... M. obliquifasciella
- Distal process of costa almost straightly bending outward, forms a right angle with valva at outside (Ren and Li, 2011).............................................................................................. M. cingillella