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 has wings? Go to 2
- Insect wingless or with poorly developed (vestigial) wings. Go to 29 - - One pair of wings (two wings). Go to 3
- Two pairs of wings (four wings). Go to 7 - - Body grasshopper-like, with enlarged hind legs and pronotum extending back over abdomen = Orthoptera
- Insects not like this. Go to 4 - - Abdomen with 'tails'. Go to 5
- Abdomen without 'tails'. Go to 6 - - Insects <5mm long, with relatively long antennae: wing with only one forked vein = Hemiptera
- Larger insects with short antennae and many wing veins: tails long = Ephemeroptera - - Fore wings forming club-shaped halteres = Strepsiptera
- Hind wings forming halteres (may be hidden) = Diptera - - Fore wings hard or leathery. Go to 8
- All wings membranous. Go to 13 - - Fore wings tough apart from membranous tip = Hemiptera
- Fore wings of uniform texture throughout. Go to 9 - - Fore wings (elytra) hard and veinless, meeting in centre line. Go to 10
- Fore wings with many veins, overlapping at least a little and often held roofwise over the body. Go to 11 - - Abdomen ending in a pair of pincer-like cerci : elytra always short = Dermaptera
- Abdomen without forceps: elytra commonly cover whole abdomen = Coleoptera - - Insects with piercing and sucking beaks = Hemiptera
- Insects with chewing mouthparts: cerci ('tails') usually present. Go to 12 - - Hind legs modified for jumping = Orthoptera
- Hind legs not modified for jumping. Go to 49 - - Tiny insects covered with white powder. Go to 14
- Insects not like this. Go to 15 - - Wings held flat at rest: mouth-parts adapted for piercing and sucking = Hemiptera
- Wings held roofwise over body at rest: biting mouthparts = Neuroptera - - Small, slender insects with narrow, hair-fringed wings: often found in flowers = Thysanoptera
- Insects not like this. Go to 16 - - Head extending downwards into a beak = Mecoptera
- No such beak. Go to 17 - - Wings more or less covered with scales: coiled proboscis (tongue) usually present = Lepidoptera
- Wings usually transparent although often hairy. Go to 18 - - Wings with a network of veins, including many cross veins. Go to 19
- Wings with relatively few cross veins. Go to 23 - - Abdomen with long terminal threads. Go to 20
- Terminal appendages short or absent. Go to 21 - - Fore wings much larger than hind wings: wings held vertically over body at rest: 2 or 3 terminal threads = Ephemeroptera
- Wings more of less equal in size or hind wings larger: wings folded close to body at rest: 2 terminal appendages = Plecoptera - - Antennae very short: body at least 25mm long = Odonata
- Antennae longer: greater than width of head. Go to 22 - - Tarsi 3-segmented = Plecoptera
- Tarsi 5-segmented = Neuroptera - - Wings noticeably hairy. Go to 24
- Wings not noticeably hairy. Go to 25 - - All wings more or less alike: front tarsi swollen = Embioptera
- Hind wings usually broader than fore wings: front tarsi not swollen = Trichoptera - - Tarsi with 4 or 5 segments. Go to 26
- Tarsi with 1 - 3 segments. Go to 27 - - All wings alike = Isoptera
- Hind wings much smaller than fore wings = Hymenoptera - - Hind wings similar to or larger than fore wings: abdomen with cerci = Plecoptera
- Hindwings smaller than fore wings: no cerci. Go to 28 - - Tiny insects with at least 12 antennal segments = Psocoptera
- Never more than 10 antennal segments: piercing and sucking beak present = Hemiptera - - Insects with slender, twig like body = Phasmatodea
- Insects not like this. Go to 30 - - Insects with grasshopper-like body and long back legs = Orthoptera
- Insects not like this. Go to 31 - - Small, soft-bodied insects living on plants, often under protective shield or scale = Hemiptera
- Insects not like this. Go to 32 - - Minute soil-living insects, <2mm long without antennae = Protura
- Insects not like this. Go to 33 - - Insects with cerci or other abdominal appendages. Go to 34
- Insects with other appendages. Go to 41 - - Abdominal appendages long and conspicuous. Go to 35
- Abdominal appendages short or hidden under body. Go to 38 - - Abdominal appendages forming pincers. Go to 36
- Abdominal appendages not forming pincers. Go to 37 - - Tarsi 3-segmented = Dermaptera
- Tarsi 1-segmented = Diplura - - Abdomen with 3 long terminal appendages = Thysanura
- Abdomen with only 2 terminal appendages = Diplura - - Tiny jumping insects, head points downwards forming a beak = Mecoptera
- No sign of beak. Go to 39 - - Small or minute insects with a forked springing organ (furcula) under rear of abdomen: generally found in soil or decaying vegetation = Collembola
- Insects not like this. Go to 40 - - Tarsi usually 4-segmented = Isoptera
- Tarsi 3-segmented: front tarsi swollen = Embioptera - - Parasites in fur or feathers: insects generally flattened side-to-side or dorso-ventrally. Go to 42
- Insects not parasitic and not usually flattened. Go to 46 - - Jumping insects flattened from side-to-side = Siphonaptera
- Insects not flattened from side-to-side. Go to 43 - - Insects of moderate size: head partly withdrawn into thorax. Go to 44
- Small minute insects: head not withdrawn into thorax. Go to 45 - - Antennae very short: very 'leggy' insects with strong claws well suited to clinging to a host mammal = Diptera
- Antennae long: body somewhat circular, with less prominant legs and claws = Hemiptera - - Prothorax distinct: biting mouthparts = Mallophaga
- Thoracic segments fused into one unit: sucking mouthparts = Anoplura - - Abdomen with pronounced 'waist': antennae often elbowed = Hymenoptera
- No such features. Go to 47 - - Body >5mm long, clothed with flattened hairs and scales: vestigial wings present = Lepidoptera
- Body usually <5mm long, bald or occasionally scaly: vestigial wings rarely present. Go to 48 - - Head a wide or nearly as wide as body: biting mouthparts: insects often found among dried materials = Psocoptera
- Head narrower than body: sucking mouthparts: abdomen often with a pair of tubular outgrowths (cornicles) near hind end: insects found on growing plants =Hemiptera - - First pair of legs raptorial (used to grasp prey) and held close to the body at rest = Praying Mantids
- Front legs not like this and body flattened = Cockroaches
This Key is based on the keys that can be found in:
Insects of Britain & Northern Europe by Michael Chinery and