Key to the species of Eudexia, modified from Santis (2021)

1. Prementum long, about 2x length of head........................................................ E. brevicornis

- Prementum short, at most 0.5x length of head............................................................... 2

2. Vertex broad, about 0.35x head width in dorsal view, legs enterally yellowish................................ E. mellea

- Vertex narrow, at most 0.15x head width in dorsal view, legs brownish, at most with some portions of femur tawny-yellowish........................................................................................... 3

3. Abdomen without pruinosity and with a dorsal brownish black median vitta interrupted from syntergite 1+2 to tergite 5.... 4

- Abdomen with whitish pruinosity on tergites 3 to 5 and with a dorsal and continuous median vitta uninterrupted from syntergite 1+2 to tergite 5....................................................................................... 5

4. Postpedicel orange; upper calypter hyaline; abdomen with an inconspicuous and narrow brownishblack median vitta.................................................................................................... E. lopesi

- Postpedicel light brown, but proximal 1/5 dark yellow; upper calypter smoky to light brown or hyaline with distal margin light brown; abdomen with a conspicuous and broad brownish black longitudinal vitta............................ E. grandis

5. Tergite 5 black, abdomen light yellow to tawny yellow in ground color........................................... 6

- Tergite 5 pale brownish, abdomen slightly reddish-yellow to yellow in ground color..................... E. colombiana

6. Postpronotal lobe, notopleuron, posterior callus and scutellum reddish-yellow in ground color............... E. dreisbachi

- Postpronotal lobe, notopleuron, posterior callus and scutellum brownish-black in ground color........................ 7

7. Upper calypter hyaline, with distal margin light brown; abdominal tergites 3 and 4 with a well-developed and conspicuous dorsal brownish black median vitta where the discal setae arise...................................... E. formidabilis

- Upper calypter dark brown; abdominal tergites 3 and 4 with a very thin dorsal brownish black median vitta and an inconspicuous median vitta where the discal setae arise.......................................................... E. orientalis