Key to the genera of Bombycinae in China

1. Forewing with strongly falcate apex.......................................................................2

- Forewing with slightly falcate or rounded apex.............................................................. 4

2. Body lightly gray or yellow; forewing with a rectangle black spot near apex; Geometridae-like day flying species with broad wings................................................................................... Rondotia Moore

- Body heavily gray or ocher; forewing with a cresent-shaped spot or without spots near apex; robust crepuscular species..... 3

3. Tornus of hindwing with a prominent recurved projection, forewing without a crescent-shaped spot near apex...................................................................................................... Gunda Walker

- Tornus of hindwing without a prominent recurved projection, forewing with a crescent-shaped spot near apex.................................................................................................. ... Bombyx Linnaeus

4. Body yellowish-brown; forewing veins connected by serrate submarginal line......................................................................................................... .. Rotunda Wang, X. & Zolotuhin, gen. nov.

- Body not yellowish-brown; forewing veins not connected by serrate submarginal line............................... 5

5. Costal and inner margins edged with yellow and black..................... Valvaribifidum Wang, X., Huang &Wang, M.

- Costal and inner margins not edged with yellow and black.....................................................6

6. Valva long slice, apex divided into two forks................................................... Ernolatia Walker

- Valva not long slice, apex not divided into two forks.......................................................... 7

7. Valva strongly developed...............................................................................8

- Valva small to completely reduced....................................................................... 10

8. Dark-colored, medium-sized species; uncus single, thin and straight; socii paired and sclerotized............................................................................................................... Triuncina Dierl

- Mostly whitish species; uncus hooked or bifurcate; socii not sclerotized.......................................... 9

9. Uncus hooked............................................................................. Bivincula Dierl

- Uncus bifurcate....................................................................... .. Gnathocinara Dierl

10. Uncus bifurcate....................................................................... .. Penicillifera Dierl

- Uncus not divided.................................................................................... 11

11. Uncus hooked............................................................................. Ocinara Walker

- Uncus straight............................................................................ Trilocha Moore