Key to the known larvae of Caenis Stephens, 1835 from South India

(Larval characters of Caenis maratha, Caenis sp. 1, and Caenis sp. 2 are unknown)

1 Cuticular coloration of femora, tibia and tarsus of each leg with contrasting dark bands (Fig. 129)... C. arunachalami sp. n.

- Cuticular coloration of femora, tibia and tarsus of each leg mostly unicolor without any contrasting dark band (Fig. 3)..... 2

2 Mesonotum with well-developed bulging at the margins (Fig. 2)...................................... C. americani

- Mesonotum with slightly-developed or no bulging at the margins (Fig. 79)........................................ 3

3 Foreclaw and midclaw without any denticulation (Figs. 80, 85)................................................. 4

- Foreclaw and midclaw with denticles (Figs. 41, 44).......................................................... 5

4 Hindclaw without any basal denticles along with row of microdenticles (Fig. 13)...................... C. maduraiensis

- Hindclaw with basal denticles along with row of microdenticles (Fig. 91)...................... C. venkataramani sp. n.

5 Forefemur with a transverse row of 12–13 spatulate setae (Srinivasan et al. 2023; Fig. 22)...................... C. limai

- Forefemur with a transverse row of 7–8 spatulate setae (Fig. 38).................................... C. kaegies sp. n.