Basic morphology of an insect whit six legs - click to enlarge
The different steps may contain scientific terms which may seem encouraged - I will recommend to search the word on google. Meanwhile, I am looking for pictures to illustrate each step - It is also the intention that these images will illustrate the foreign words. Can you help or do you maybe have access to such images, then I would be very happy to hear from you. Contact me here
- - Insect with wings or wingcases, Go to 2
- Insect without wings, Go to 27 - - Insects with four wings (two pairs), Go to 3
- Insects with only two wings (one pair), Go to 25 - - Wings covered with scales = Butterflies and Moths (Lepidoptera)
- Wings not covered with scales, though they may be hairy, Go to 4 - - Fore-wings partly or entirely horny or leathery and used as covers for
hind-wings often much narrower than hindwings, Go to 5
- Both pairs of wings entirley membranous (flexible) and used for flying,
Go to 12 - - Mouth-parts tube-like, adapted for piercing and sucking = True Bugs (Hemiptera)
- Mouth-parts adapted for biting and chewing, Go to 6 - - Fore-wings and hind-wings with veins, hind-wings stiffer and harder than
and serving as covers for hind-wings, Go to 7
- Fore-wings without veins, and modified into hard, horny cases for hind-wings, Go to 10 - - Body dorsoventrally flattened = Cockroaches Dictyoptera; (Blattodea)
- Body rounded or quadrate in section, Go to 8 - - Forelegs raptorial, adapted for grasping and holding = Preying Mantids, (Dictyoptera; Mantodea)
- Forelegs not raptorial, Go to 9 - - Prothorax as large as or larger than meso and meta thorax, hind legs generally enlarged and adapted for jumping = Grasshoppers and Crickets (Orthoptera)
- Prothorax smaller than meso and meta thorax, legs normally similar in thickness, if hind legs enlarged then not used for jumping = Stick-Insects (Phasmida) - - Fore-wings short, Go to 11
- Fore-wings as long as, or nearly as long as abdomen the 2 wings may be joined where they meet along the animals back and hence never used for flying = Beetles (Coleoptera) - - End of abdomen with characteristic pair of forceps like cerci = Earwigs, (Dermaptera)
- End of abdomen with out characteristic forceps like cerci = Beetles (Coleoptera; Staphylinidae) - - Wings narrow and without veins, but fringed with long hairs. Very small insects, about 5 mm in length = Thrips (Thysanoptera)
- Wings more fully developed, and with veins present, Go to 13 - - Hind-wings noticeably smaller than fore-wings, Go to 14
- Hind-wings similar in size to or larger than fore-wings, Go to 19 - - Abdomen with two or three long 'tails'. Fore-wings with a large number of cross-veins, making a net-like pattern = Mayflies (Ephemeroptera)
- Fore-wings with fewer veins, not forming a net-like pattern, usually without 'tails', Go to 15 - - Wings obviously hairy. Mouth-parts very small, except forpalpi = Caddisflies (Trichoptera)
- Wings not obviously hairy, though tiny hairs can be seen under the microscope, Go to 16 - - Mouth-parts well developed and adapted for biting and chewing, Go to 17
- Mouth-parts tube-like, adapted for piercing and sucking = Aphids; Cicadas etc,. (Hemiptera; Homoptera) - - Very small insects, soft-bodied, mostly less than 6 mm. in length. tarsi with only two or three segments, Go to 18
- Often much bigger, wasp-like or bee-like insects; or if very small, then hard-bodied, with abdomen narrowed at its base into a petiole, or 'waist'. tarsi with four or five segments = Bees, Wasps, Ants and Sawflies (Hymenoptera) - - Antennae with 9 segments only =rare Zoraptera
- Antennae with 12 to 50 segments = Bark or Book Lice (Psocoptera) - - Tarsi with three or four segments only, Go to 20
- Tarsi with five segments, Go to 23 - - Tarsi with 3 segments only; first segment of anterior (front) legs greatly swollen = Webspinners (Embioptera)
- Tarsi with 3 or 4 segments, if 3 then first segment of anterior legs not swollen, Go to 21 - - Wings with few cross-veins, fore-wings differently shaped to hind-wings which are greatly expanded posteriorly = Stoneflies (Plecoptera)
- Wings with numerous cross veins, fore- and hind-wings usually very similar in shape,though hind-wings occasionally enlarged posteriorly, Go to 22 - - Small insects, generally much less than 1 inch. (25 mm.) in length with long antennae, and with wings folded flat over body = Termites (Isoptera)
- Generally longer than 1 inch., with very short antennae. Wings held away from body when at rest = Dragonflies (Odonata) - - Mouth-parts prolonged into a beak = Scorpionflies (Mecoptera)
- Mouth-parts short, Go to 24 - - Most of the veins in forewings divide or fork just before they reach the wing edge, hind-wings broader than fore-wings at least at base = Alderflies, Snakeflies, (Megaloptera)
- Few or no veins in the forewings fork immediatley before the wing edge, hind-wings similar to fore-wings = Lacewings (Neuroptera) - - Hind-wings absent or reduced knob-like organs (called halteres), Go to 26
- Forewings absent or reduced to knob-like organ = Stylops (Strepsiptera) - - Hind-wings reduced or modified to knob-like organs (called halteres) Mouth-parts of various forms = True Flies Diptera (Also males of Homoptera, family Coccidae, but these are very rare)
- Hind-wings entirely absent; no halteres = Some Mayflies (Ephemeroptera) - - Some segments with jointed legs, which can be used for movement, Go to 28
- No jointed legs; or if these are present and visible, then they are enclosed in membrane, and cannot move = Larvae and Pupae of Endopterygota (You will need specialised keys to get these to order) - - Animals found living as parasites on warm-blooded animals, or found closely associated with them i.e. in their nests or dens, Go to 29
- Animals not found living as parasites on warm-blooded animals: either freeliving, or parasitic on other insects, snails etc., Go to 34 - - Body flattened from side to side, hard and bristly, with strong legs, jumping insects, found on birds and mammals = Fleas (Siphonaptera)
- Insects not as above, body either rounded or flattened from above, Go to 30 - - Mouth-parts adapted for biting and or chewing, Go to 31
- Mouth-parts adapted for piercing and or sucking, Go to 32 - - Posterior end of the body with cerci. Found on bats and small rodents in tropical environments only = Parasitic earwigs (Dermaptera)
- Posterior end of body without cerci. On birds or mammals all over the world = Chewing lice (Mallophaga) - - Flattened, rather spider-like insects, with head fitting into a notch on thorax, and with antennae not visible. Claws hooked = Louseflies and Batflies (Diptera)
- Not spider-like. Antennae clearly visible, Go to 33 - - Snout (proboscis) short, unjointed. Body long and narrow. Tarsi of legs with one large, hooked claw. Permanent parasites of birds and mammals = Sucking lice, (Anoplura)
- Snout (proboscis) longer, jointed. Body more oval. tarsi with two small claws, not hook-like. Only temporary parasites = Wingless bugs (Hemiptera) - - Terrestrial: living on dry land, or on animals other than mammals and birds, Go to 35
- Aquatic: mostly nymphal forms of terrestrial insects, Go to 60 - - Mouth-parts not visible. Abdomen with appendages on some of the abdominal segments, or with a forked 'spring' near tip, Go to 36
- Mouth-parts clearly visible, Go to 39 - - Abdomen with six segments or fewer, usually with a forked appendage ('spring') near tip. No long bristles at tip of abdomen = Springtails (Collembola)
- Abdomen with nine or more segments. No spring, but several segments have simple appendages, Go to 37 - - Cerci present, sometimes appearing as clasping forceps, Go to 38
- No cerci = Protura - - A central 'cerciform tergum' projects between the cerci giving the appearance of 3 'tails' = 3-Pronged Bristletails (Thysanura)
- No central 'cerciform tergum', hence having the appearance of 2 'tails' =
2-Pronged Bristletails (Diplura) - -Mouthparts mostly adapted for piercing or sucking, Go to 40
- Mouth-parts not as above, adapted for biting and or chewing, Go to 44 - - Body covered with scales and or dense hairs = Wingless Moths (Lepidoptera)
- Body bare, or with few scattered hairs, Go to 41 - - Almost all of thorax that is visible above is composed of the middle segment, -the mesothorax: prothorax and metathorax both small and hidden = Wingless True flies (Diptera)
- Mesothorax and metathorax about equally developed. Prothorax also is usually visible from above, Go to 42 - - Snout (proboscis) small, cone-shaped. Body long and narrow. Claws usually absent = Thrips (Thysanoptera)
- Snout (proboscis) longer, jointed. Body more or less oval. Claws present, Go to 43 - - Proboscis arising from front part of head. Abdomen without cornicles near tip = Wingless Bugs (Hemiptera)
- Proboscis arising from hind part of head. Abdomen often with two cornicles at or near its tip = Aphids (Hemiptera; Homoptera) - - Abdomen with false or pro-legs, which are fleshy, and different from the jointed legs of the thorax. Caterpillar-like, Go to 45
- Abdomen without any kind of legs, only thorax has legs, Go to 47 - - Five pairs of prolegs, or fewer, with minute hooks (crochets); none on the1st or 2nd abdominal segments = Caterpillars (Lepidoptera)
- Six to ten pairs of prolegs, always with one pair on the 2nd abdominal segment. No crochets present, Go to 46 - - Head with a single ocellus (small eye) on each side = Larvae of Sawflies, (Hymenoptera; Symphyta)
- Head with several ocelli on each side = Larvae of Scorpionflies, (Mecoptera) - - Antennae short and indistinct. Larvae, Go to 48
- Antennae long and distinct. Adult insects, Go to 50 - - Body Caterpillar-like, Go to 49
- Body not caterpillar-like = Larvae of some endopterygote insects (Neuroptera or Coleoptera) - - Head with six ocelli on each side of headsome = Caterpillars (Lepidoptera)
- Head with more than six ocelli on each side = Larvae of some Mecoptera - - Abdomen with a pair of movable forceps like cerci at tip = Earwigs (Dermaptera)
- Abdomen without such forceps, Go to 51 - - Abdomen strongly constricted at base into a 'waist'. Sometimes antennae are bent into an elbow = Ants and wingless Wasps (Hymenoptera)
- Abdomen not constricted into a waist, Go to 52 - - Head prolonged underneath body into a long beak, which bears mandibles at its tip = Scorpionflies (Mecoptera)
- Head not prolonged into a beak, Go to 53 - - Tiny soft insects, Go to 54
- Fairly small, to very big, usually hard-bodied insect, Go to 55 - - Cerci absent = Booklice and Barklice (Psocoptera)
- Cerci present = Zoraptera - - Hind-legs enlarged for jumping = Grasshoppers/Crickets, (Saltatoria; Orthoptera)
- Hind-legs not enlarged for jumping, Go to 56 - - Tarsi of legs with four segments. Pale, soft-bodied insects living in wood or soil = Termites (Isoptera)
- Tarsi of legs with five segments. More highly coloured insects, Go to 57 - - Body dorsoventrally flattened = Cockroaches Dictyoptera; (Blattodae)
- Body not dorsoventrally flattened rounded or squarish in section, Go to 58 - - Cerci long, containing 8 segments, eyes reduced or absent= Grylloblattodae
- Cerci not as above, eyes well developed, Go to 59 - - Fore-legs modified for grasping and holding, predatory = Dictyoptera; Mantodae
- Fore-legs not so modified = Stick Insects (Phasmida) - - Mouth-parts adapted for piercing and sucking = Nymphs of Water-bugs, (Hemiptera and larvae of some Neuroptera)
- Mouth-parts adapted for licking and chewing, Go to 61 - - Body enclosed in a case made of pebbles, sand and debris = Larvae of Caddisflies, (Trichoptera)
- Body not enclosed in such a case, Go to 62 - - Abdomen with external gills, Go to 63
- Abdomen without external gills, Go to 64 - - With two or three long processes at tip of abdomen, traces of wing-cases may be visible in later instars = nymphs of Mayflies (Ephemeroptera)
- Only one process at tip of abdomen, and no wing-cases visible = Alderflies, (Megaloptera; Sialioidea) - - Head with a 'mask', bearing the jaws which is capable of being extended far forwards of the insect's body = Nymphs of Dragonflies (Odonata)
- Head without such a mask, Go to 65 - - With long antennae; and long filaments at tip of abdomen = Larvae of Stoneflies, (Plecoptera)
- Without such filaments = Larvae of Beetles (Coleoptera)
and diffently worth a look. The Key is adapted from Harold Oldroyd 1958