Key to species in the genus Ewartia

1. Specimen mainly medium brown to dark brown or green to brown with a brown or red central stripe along dorsum (eastern or northern Australia)....................................................................................2

- Specimen uniform pale green to yellow-brown, lacking a brown or red central stripe (central Western Australia)..... cuensis

2. Central fascia of pronotum either darker than or similar to remainder of pronotum..................................3

- Central fascia of pronotum yellow-brown and distinctly paler than remainder of pronotum (Cooktown to Cape York, northern Queensland)..................................................................................... .. brevis

3. Head width 3.5–4.5 mm; pronotum greenish to yellow-brown, typically without a brown central fascia (southern edge of the Top End of the Northern Territory)........................................................... thamna (Fig. 2 E)

- Head width 4.9–7.0 mm; pronotum greenish or olive-brown, typically with a dark brown, brown or reddish central fascia...4

4. Thorax with lateral sigilla on mesonotum clearly paler than submedian sigilla; specimen mainly green with a conspicuous brown stripe medially along dorsum.......................................................................5

- Thorax with lateral sigilla and submedian sigilla on mesonotum both equally dark brown to black; specimen mainly medium brown to dark brown (Cape York, northern Queensland).......................................... .. carina (Fig. 2 F)

5. Central fascia of pronotum reddish or dark brown; the anterior portion of this fascia being wider than the inner margins of the lateral ocelli.......................................................................................... 6

- Central fascia of pronotum medium brown; the anterior portion of this fascia being narrower than the inner margins of the lateral ocelli (southern Queensland to mid-northern New South Wales)................................. roberti (Fig 2 B)

6. Head width <5.9 mm; female ovipositor extends approximately 3 mm beyond the apex of abdominal segment 9 (Top End of the Northern Territory)..................................................................... etesia (Fig. 2 D)

- Head width typically> 5.9 mm; female ovipositor extends <2.6 mm beyond the apex of abdominal segment 9............ 7

7. Central fascia of pronotum broadens posteriorly to margin of pronotal collar; female ovipositor extends 2.0– 2.5 mm beyond the apex of abdominal segment 9 (south-eastern Queensland north to the Tropic of Capricorn)........... oldfieldi (Fig. 2 A)

- Central fascia of pronotum broadens posteriorly, then narrows abruptly anterior to margin of pronotal collar; female ovipositor extends <0.5 mm beyond the apex of abdominal segment 9 (inland Queensland and New South Wales).... lapidosa (Fig. 2 C)