Key to the Indian species of Mothocya
1. Body widest at pereonites 4 and 5 scarcely twisted; coxae on pereonite 7 less produced laterally....................... 2
- Body widest at pereonites 5 and 6 weakly twisted to one side; coxae on pereonite 7 largely produced (as long as wide)..... 3
2. Pleonite 5 lesser than the other pleonites; pleotelson subtruncate and wide.............. Mothocya karobran (Bruce, 1986)
- Pleonite 5 wider than the other pleonites; pleotelson large (as wide or wider than pleon) and evenly rounded................................................................................... Mothocya plagulophora (Haller, 1880)
3. Pleopods not extending posterior margin of pleotelson; uropod extending beyond posterior margin of pleotelson..................................................................... Mothocya melanosticta (Schiƶedte & Meinert, 1884)
- Pleopods extending posterior margin of pleotelson; uropod extending beyond posterior margin of pleotelson............. 4
4. Coxae expressed laterally, but less wide; Pereopod 7 basis without carinae.............. Mothocya renardi (Bleeker, 1857)
- Coxae strongly expressed laterally, very wide; Pereopod 7 basis with carinae.............. Mothocya collettei Bruce, 1986