Suborders

1.  
   • Fore and hind wings similar in shape and usually in venation; discoidal cell quadrangular, never longitudinally divided; ♂ inferior appendages paired, below anus. Larvae usually slender, with 3 (exceptionally only 2) large caudal gills ZYGOPTERA
   • Fore and hind wings dissimilar in venation and usually in shape; discoidal cell divided longitudinally into 'triangle' and 'hypertriangle'; one median inferior appendage in ♂, above anus. Larvae stout, without caudal gills, but with an anal pyramid ANISOPTERA

Zygoptera families & subfamilies

1.  
   • Normally 2 antenodal cross-veins, both extending across costal and subcostal spaces (Figs 17.14--18) 2
   • Several antenodal cross-veins, the extra veins not necessarily extending across both costal and subcostal spaces (Fig. 17.19) 11
2. (1)
   • Anal vein vestigial or absent, so that there are no longitudinal veins behind CuP beyond the discoidal cell (Figs 17.14,15) 3
   • Anal vein long, straight or zigzagged, extending well beyond level of subnodus (Figs 17.16--18) 5
3. (2)
   • Anterior sector of arculus (Rs) forking about a third to half of the way from arculus to level of subnodus (Fig. 17.15) Lestoideidae
   • Anterior sector of arculus forking well beyond half-way from arculus to subnodus, sometimes beyond subnodus (Fig. 17.14) 4
4. (3)
   • Black marked with cream, green, blue or orange; CuP 2 cells or less long, commonly 1 cell Protoneuridae
   • Pale brown to dark greenish grey, rarely black, thorax and abdomen sometimes pruinescent; CuP of variable length, 1-several cells long Isostictidae
5. (2)
   • Arculus of fore wing missing, so that discoidal cell is open at base 6
   • Arculus of fore wing normal, discoidal cell closed at base 7
6. (5)
   • CuP strongly arched forward in first cell after it leaves posterior distal corner of discoidal cell (cf. Fig. 17.18) Synlestidae - CHORISMAGRIONINAE
   • CuP almost straight in first cell beyond discoidal cell Hemiphlebiidae
7. (5)
   • No supplementary longitudinal veins between branches of Rs (R2, IR2, R3, IR3 and R4) in distal part of wing Coenagrionidae
   • At least 1 supplementary, intercalated vein between branches of Rs in distal part of wing 8
8. (7)
   • Anterior sector of arculus (Rs) forking less than half-way from arculus to level of subnodus (Fig. 17.17) Lestidae 9
   • Anterior sector of arculus forking well beyond half-way from arculus to level of subnodus (Fig. 17.4A) 10
9. (8)
   • Discoidal cells similar in shape in fore and hind wings LESTINAE
   • Discoidal cell of hind wing conspicuously longer than that of fore wing SYMPECMATINAE
10. (8)
    • CuP strongly arched forward in first cell after it leaves posterior corner of discoidal cell (Fig. 17.18) Synlestidae - SYNLESTINAE
    • CuP almost straight in first cell beyond discoidal cell (Fig. 17.4A) Megapodagrionidae
11. (1)
    • Only the 2 basal antenodal cross-veins extending across both costal and subcostal spaces, the additional cross-veins confined to the costal space (Fig. 17.19) Amphipterygidae
    • Numerous antenodal cross-veins in both the costal and subcostal spaces 12
12. (11)
    • Abdomen much longer than wings; pterostigma absent Calopterygidae
    • Abdomen shorter than wings; pterostigma present Chlorocyphidae

Anisoptera families & some subfamilies

1.  
   • Compound eyes widely separated on top of head 2
   • Eyes close together on top of head or, most commonly, narrowly or broadly fused in midline 4
2. (1)
   • Male with broad, leaf-like superior anal appendages; female with complex ovipositor bearing pair of styli near tip, which extends to or beyond end of abdominal segment 10 Petaluridae
   • Male superior appendages relatively slender, more or less rounded in section; ovipositor reduced to scale-like structure rarely extending beyond end of abdominal segment 9, and lacking styli Gomphidae 3
3. (2)
   • Triangle of fore and hind wing traversed by cross-veins; hind wing more than 33 mm long ICTINOGOMPHINAE
   • Triangle of fore and, usually, of hind wing entire; hind wing shorter than 33 mm GOMPHINAE
4. (1)
   • Triangle of fore wing elongate along wing axis (Fig. 17.4B) 5
   • Triangle of fore wing not elongate along wing axis, often elongate across it (Fig. 17.23) 9
5. (4)
   • Anterior part of both wings marked with series of rounded, reddish brown spots Neopetaliidae
   • Anterior part of wings colourless except for pterostigma, or marked with brown stripe, sometimes subdivided into bands and broad, rounded nodal spot Aeshnidae 6
6. (5)
   • MA unbroken distally and running parallel to, or diverging from, R4 (Fig. 17.4B) BRACHYTRONINAE
   • MA degenerate distally and converging upon R4 7
7. (6)
   • Anal appendages very long and thin; [Zf] dentigerous plate a 2- or 3-pronged digging-fork GYNACANTHAGINAE
   • Anal appendages and dentigerous plate not as above 8
8. (7)
   • R3 smooth distally; anal triangle in hind wing of [Zm] well developed AESHNINAE
   • R3 kinked forward distally; anal triangle absent ANACTINAE
9. (4)
   • Cross-veins present in median space (Fig. 17.21) Corduliidae - SYNTHEMISTINAE
   • No cross-veins in median space (Fig. 17.22) 10
10. (9)
    • Basal side of hind wing triangle far beyond arculus, separated from it by a distance equal to or greater than the length of the arculus 11
    • Basal side of hind wing triangle nearer to arculus, up to approximately half the length of arculus beyond it, often in line with it 13
11. (10)
    • Large species, hind wing more than 35 mm long Corduliidae - MACROMIINAE
    • Small species, hind wing less than 35 mm long 12
12. (11)
    • Sectors of arculus separating closer to arculus than to first cross-vein beyond it; male with auricles and angulated base to hind wing Corduliidae - CORDULEPHYINAE
    • Sectors of arculus separating abruptly close to first cross-vein beyond arculus; male lacking auricles, hind wing rounded at base Libellulidae (pt)
13. (10)
    • Sectors of arculus fused at their origins and forming a short stalk (except in the fore wing of some Rhyothemis); wing coloration variable, often with dark general, nodal or distal pigmentation (including Rhyothemis) Libellulidae (pt)
    • Sectors of arculus diverging from their origins (at least in fore wing); wings hyaline or partly suffused yellow or pale orange, with or without yellow to reddish brown marks at their bases 14
14. (13)
    • Basal side of hind wing triangle at or slightly basal to arculus; anal loop stocking-shaped, expanded, with extra cells, at tip (not necessarily in Metaphya) Corduliidae - CORDULIINAE
    • Basal side of hind wing triangle slightly to well beyond arculus; anal loop compact to sausage-shaped, not expanded, and without extra cells, at tip (except occasionally in Hesperocordulia) Corduliidae - GOMPHOMACROMIINAE

Downloadable Key

Odonata – A Key to Australian Families (interactive PDF) has been provided for download by JWH Trueman, Australian National University.

*Note

The dichotomous key from The Insects of Australia (Second Edition, 1991) has also been provided. This key is presented as it originally appeared; no attempt to update it or the classification has been made.