What Bug Is That? The guide to Australian insect families.

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Identify families


    • 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

    • 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

    • 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.


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.