Identifying Insects
Collecting insects or other invertebrates (animals that do not have a backbone) is an excellent way to observe environments and discover biodiversity in the local area. However collectors usually want to classify the insects they have collected to species level. Species level identification of even common insects can be a very difficult business, even for professional entomologists. The most that should be expected is classification of larger species to Order level. This simple key will enable this to be done, usually without having to use a microscope.
For more information about Queensland insects download the fact sheets from our Inquiry Centre.
Key to Orders of Common Larger Adult Insects
An identification key consists of a series of numbered couplets. Each couplet has two opposing statements, "a" and "b", only one of which applies to your specimen. Begin at Couplet 1 and decide if your specimen agrees with "a" or "b". Move to the next couplet as instructed. Eventually this process will lead to the taxonomic order your specimen belongs to.
1. | (a) One or two pairs of well-developed wings present, though often folded along body and inconspicuous | Go to Couplet 2 |
(b) Wings absent, or present only as small pads or scales less than half length of abdomen | Go to Couplet 21 | |
2. | (a) Only the front pair of wings present | Go to Couplet 3 |
(b) Two pairs of wings present, hindwings may be concealed beneath protective forewings | Go to Couplet 4 | |
3. | (a) Front wings hard, opaque, forming protective cover over abdomen, not used for flying | Order 22. COLEOPTERA |
(b) Front wings membranous, not forming covers, used for flying | Order 26. DIPTERA | |
4. | (a) Front wings hard and opaque, at rest forming close-fitting covers for the transparent hindwings; front wings with no branching veins except sometimes just at the apex | Go to Couplet 5 |
(b) Front wings either transparent, or with branching veins over most of surface, or not forming close-fitting covers over hindwings | Go to Couplet 7 | |
5. | (a) Mouthparts forming a cylindrical sucking rostrum beneath head, often folded between the forelegs; palps absent | Order 18. HEMIPTERA |
(b) Mouthparts not forming a rostrum; palps present on mouthparts | Go to Couplet 6 | |
6. | (a) Abdomen with prominent, pincer-like forceps at end; front wings much shorter than abdomen | Order 11. DERMAPTERA |
(b) Abdomen without prominent, movable forceps; front wings usually as long as abdomen | Order 22. COLEOPTERA | |
7. | (a) Wings covered with microscopic, overlapping scales which easily rub off; mouthparts forming a coiled, sucking proboscis (sometimes absent) beneath the head | Order 28. LEPIDOPTERA |
(b) Wings usually bare or hairy; mouthparts not forming a coiled tube | Go to Couplet 8 | |
8. | (a) Abdomen usually with 3 long, flexible, segmented filaments at its rear end; if with two filaments then front wings much larger in area than hindwings | Order 6. EPHEMEROPTERA |
(b) Abdomen usually without 3 long segmented filaments; if with 2 filaments (cerci) then front wings not larger than hindwings (a long central ovipositor may be present in some females but it is not segmented as in the filaments of Ephemeroptera) | Go to Couplet 9 | |
9. | (a) Mouthparts forming a straight, cylindrical rostrum, sometimes concealed between forelegs; palps absent | Order 18. HEMIPTERA |
(b) Mouthparts not forming a true rostrum, sometimes elongate but then 2 or more palps are present | Go to Couplet 10 | |
10. | (a) Forewings thicker and more opaque than hindwings and forming a protective cover for them | Go to Couplet 11 |
(b) Both pairs of wings of similar texture | Go to Couplet 14 | |
11. | (a) Forelegs armed with spines and modified for seizing prey; prothorax very long | Order 10. MANTODEA |
(b) Forelegs not modified for seizing prey; prothorax usually not long | Go to Couplet 12 | |
12. | (a) Body long and narrow, stick- or leaf-like in form; hindlegs not modified for jumping | Order 14. PHASMATODEA |
(b) Body long and narrow, the hindlegs modified for jumping | Go to Couplet 13 | |
13. | (a) Thorax covering head when insect viewed from above; hindlegs not modified for jumping | Order 8. BLATTODEA |
(b) Head visible when insect viewed from above; hindlegs with femora enlarged for jumping | Order 13. ORTHOPTERA | |
14. | (a) Antennae minute, bristle-like, shorter than the width of an eye and having only 5-8 segments; wings flat, unfolded | Order 7. ODONATA |
(b) Antennae normal, longer than width of an eye and having more than 8 segments; wings often folded or pleated when at rest | Go to Couplet 15 | |
15. | (a) Wings with many veins and cross veins forming a close network over much of wing surface; two cerci sometimes present at tip of abdomen | Go to Couplet 16 |
(b) Cross veins few in number; cerci absent | Order 29. HYMENOPTERA | |
16. | (a) Wings deciduous, with a fracture line across their base; veins thickened along the leading edge of wing | Order 9. ISOPTERA |
(b) Wings not deciduous; all wing veins of about equal thickness | Go to Couplet 17 | |
17. | (a) Two segmented cerci present at tip of abdomen; body and wings never hairy | Order 12. PLECOPTERA |
(b) Cerci absent, or small and unsegmented; body and/or wings often hairy | Go to Couplet 18 | |
18. | (a) Mandibles absent; moth-like insects with hairy wings | Order 27. TRICHOPTERA |
(b) Mandibles present; usually not moth-like | Go to Couplet 19 | |
19. | (a) Head drawn out into an elongate beak with mouthparts at apex | Order 24. MECOPTERA |
(b) Head not noticeably beak-like | Go to Couplet 20 | |
20. | (a) Wing veins forking just before they reach edge of wing | Order 21. NEUROPTERA |
(b) Wing veins not forking just before they reach the edge of wing | Order 20. MEGALOPTERA | |
21. | (a) Abdomen terminating in 3 long segmented filaments | Order 4 THYSANURA |
(b) Abdomen with none or 2 terminal segmented filaments (a long central ovipositor may be present in some females but it is not segmented) | Go to Couplet 22 | |
22. | (a) Abdomen terminating in a pair of stout, pincerlike forceps | Order 11. DERMAPTERA |
(b) Abdomen without terminal forceps | Go to Couplet 23 | |
23. | (a) Mouthparts forming a cylindrical rostrum beneath the head; palps absent | Order 18. HEMIPTERA |
(b) Mouthparts not a rostrum; palps present | Go to Couplet 24 | |
24. | (a) Abdomen constricted to a narrow waist just behind the forebody | Order 29. HYMENOPTERA |
(b) Abdomen without a narrow waist | Go to Couplet 25 | |
25. | (a) Prothorax much longer than mesothorax, sometimes concealing the head when viewed from above | Go to Couplet 26 |
(b) Prothorax small, not much longer than mesothorax, never concealing the head | Go to Couplet 27 | |
26. | (a)Body broad and flattened; hindlegs not modified for jumping | Order 8. BLATTODEA |
(b) Body more or less cylindrical; hindlegs with enlarged femora for jumping | Order 13. ORTHOPTERA | |
27. | (a) Large, elongate, camouflaged stick- or leaf-like insects | Order 14. PHASMATODEA |
(b) Small ant-like insects; body not markedly elongate, not camouflaged | Order 9. ISOPTERA |