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Red & Blue Damsel (Xanthagrion erythroneurum)

The Red & Blue Damsel (Xanthagrion erythroneurum) is a damselfly species of the family Coenagrionidae, which contains 30 species in Australia.

The identification key to the family Coenagrionidae consists of 54 couplets, 9 of which are pertinent to Xanthagrion erythroneurum. Click on the numbers on the right to display the corresponding couplets. Or click on the ALLin1 button to see all the relevant couplets together in a single, scrollable window.

#FamilySpeciesCouplet No.
 CoenagrionidaeRed & Blue Damsel
(Xanthagrion erythroneurum)
  • Coenagrionidae: Key couplet 1 of 54

  • ○ Damselflies without this combination of characters
  • b ↑
  • Coenagrionidae: Key couplet 14 of 54

  • couplet drawing
  • ● Anal vein leaving wing margin nearer to or beyond level of Ac
    ● Basal segment of hindwing anal vein, if present, not more than half length of Ac
  • b ↑
  • Coenagrionidae: Key couplet 35 of 54

  • ○ Damselflies with dark brown or black markings on pale background (reddish, yellow, green, blue, pale brown), or substantially dark, the dark areas in either case often with metallic sheen
  • b ↑
  • Coenagrionidae: Key couplet 37 of 54

  • couplet drawingcouplet drawing
  • ● Pterostigma of forewing similar in size to that of hindwing
    ● Female lacking ventral spine on abdominal segment 8
  • b ↑
  • Coenagrionidae: Key couplet 38 of 54

  • couplet drawing
  • ● Pterostigma markedly longer than wide
  • b ↑
  • Coenagrionidae: Key couplet 40 of 54

  • ○ Extensive dull orange to red markings on head, thorax and anterior abdomen

    ⇒ species: Red & Blue Damsel (Xanthagrion erythroneurum)
  • a ↑
  • Coenagrionidae: Key couplet 48 of 54

  • couplet drawing
  • ● Posterior lobe of pronotum without forwardly directed, finger-like process on each side
  • b ↑
  • Coenagrionidae: Key couplet 50 of 54

  • couplet drawing
  • ○ Upper surface of abdominal segment 1 brown to black, with or without orange-brown dorsal and lateral marks
    ● Anal vein leaving wing margin at Ac
  • b ↑
  • Coenagrionidae: Key couplet 51 of 54

  • ○ Synthoracic terga, between wing bases, pale orange
    ○ Abdominal tergum 1 with triangular bronze dorsal mark partly divided by anterior, orange mid-dorsal line

    ⇒ species: Red & Blue Damsel (Xanthagrion erythroneurum)
  • a ↑
1  
  • Coenagrionidae: Key couplet 1 of 54

  • couplet drawing
  • ● Arculus in hindwing situated beyond distal antenodal crossvein by at least the length of subcostal part of antenodal
    ○ Very small damselflies, hindwing shorter than 14 mm

    ⇒ genus: Agriocnemis
a ↑
b ↓
  • ○ Damselflies without this combination of characters

2  
  • Coenagrionidae: Key couplet 14 of 54

  • couplet drawing
  • ● Anal vein leaving wing margin well basal to the level of Ac in both wings, so there is a basal segment of anal vein about the same length as Ac
a ↑
b ↓
  • couplet drawing
  • ● Anal vein leaving wing margin nearer to or beyond level of Ac
    ● Basal segment of hindwing anal vein, if present, not more than half length of Ac

3  
  • Coenagrionidae: Key couplet 35 of 54

  • ○ Orange-red to yellowish green damselflies without dark thoracic markings
a ↑
b ↓
  • ○ Damselflies with dark brown or black markings on pale background (reddish, yellow, green, blue, pale brown), or substantially dark, the dark areas in either case often with metallic sheen

4  
  • Coenagrionidae: Key couplet 37 of 54

  • couplet drawingcouplet drawing
  • ● Pterostigma of forewing markedly larger than that of hindwing
    ● Female with ventral spine on apex of abdominal segment 8

    ⇒ species: Blue Slim (Aciagrion fragile)
a ↑
b ↓
  • couplet drawingcouplet drawing
  • ● Pterostigma of forewing similar in size to that of hindwing
    ● Female lacking ventral spine on abdominal segment 8

5  
  • Coenagrionidae: Key couplet 38 of 54

  • couplet drawing
  • ● Pterostigma very small, almost as long as wide

    ⇒ species: Blue-Banded Longtail (Archibasis mimetes)
a ↑
b ↓
  • couplet drawing
  • ● Pterostigma markedly longer than wide

6 Male only
  • Coenagrionidae: Key couplet 40 of 54

  • ○ Extensive dull orange to red markings on head, thorax and anterior abdomen

    ⇒ species: Red & Blue Damsel (Xanthagrion erythroneurum)
a ↑
b ↓
  • ○ No such markings on thorax or abdomen

7 Female only
  • Coenagrionidae: Key couplet 48 of 54

  • couplet drawing
  • ● Posterior lobe of pronotum with forwardly directed, finger-like process on each side
a ↑
b ↓
  • couplet drawing
  • ● Posterior lobe of pronotum without forwardly directed, finger-like process on each side

8 Female only
  • Coenagrionidae: Key couplet 50 of 54

  • couplet drawing
  • ○ Posterior half of upper surface of abdominal tergum 1, excluding membrane, blue
    ● Anal vein leaving wing margin basal to Ac, forming short stalk

    ⇒ species: Swamp Bluet (Coenagrion lyelli) (part)
a ↑
b ↓
  • couplet drawing
  • ○ Upper surface of abdominal segment 1 brown to black, with or without orange-brown dorsal and lateral marks
    ● Anal vein leaving wing margin at Ac

9 Female only
  • Coenagrionidae: Key couplet 51 of 54

  • ○ Synthoracic terga, between wing bases, pale orange
    ○ Abdominal tergum 1 with triangular bronze dorsal mark partly divided by anterior, orange mid-dorsal line

    ⇒ species: Red & Blue Damsel (Xanthagrion erythroneurum)
a ↑
b ↓
  • ○ Synthoracic terga partially dark brown to black
    ○ Abdominal tergum 1 with triangular to parallel-sided dark brown to black dorsal mark lacking pale mid-dorsal line

    ⇒ genus: Austroagrion

Australian distribution