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

(Egg characters of Caenis maratha are unknown)

1 Egg with two epithemata (Fig. 4)......................................................................... 2

- Egg with a single epithema (Fig. 54)...................................................................... 4

2 Epithemata cap-like (Fig. 97)......................................................... C. venkataramani sp. n.

- Epithemata thread-like (Fig. 5)........................................................................... 3

3 Mouth of the micropyle broadened (Fig. 7)....................................................... C. americani

- Mouth of the micropyle not broadened (Fig. 17)................................................. C. maduraiensis

4 Epithema cap-like (Fig. 55)................................................................ C. kaegies sp. n.

- Epithema thread-like (Fig. 140).......................................................................... 5

5 Epithema of coiled-rope type without any terminal knobs (Figs. 140, 141)........................................ 6

- Epithema of coiled-rope type with terminal knobs (Figs. 154................................................... 7

6 Micropyle ca. 3 times the mouth width, mouth broadened (Fig. 142).......................... C. arunachalami sp. n.

- Micropyle ca. 2 times the mouth width, mouth not broadened (Fig. 151)................................. Caenis sp. 1

7 Chorion finely pored (Srinivasan et al. 2023; Fig. 42).................................................... C. limai

- Chorion smooth (Fig. 156)..................................................................... Caenis sp. 2