Key to Adult Insects

 

Key to Adult Insects

Start at Question 1 and follow the links until you’ve identified your insect

1

Insect has wings?

Go to 2

Insect wingless or with poorly developed wings

 

Go to 29

2

One pair of wings

Go to 3

Two pairs of wings

 

Go to 7

3

Body grasshopper-like, with enlarged hind legs and pronotum extending back over abdomen

Orthoptera

Insects not like this

 

Go to 4

4

Abdomen with ‘tails’

Go to 5

Abdomen without ‘tails’

 

Go to 6

5

Insects <5mm long, with relatively lonbg antennae: wing with only one forked vein

Hemiptera

Larger insects with short antennae and many wing veins: tails long

 

Ephemeroptera

6

Forewings forming club-shaped halteres

Strepsiptera

Hind wings forming halteres (may be hidden)

 

Diptera

7

Forewings hard or leathery

Go to 8

All wings membranous

 

Go to 13

8

Forewings horny apart from membranous tip

Hemiptera

Forewings of uniform texture throughout

 

Go to 9

9

Forewings (elytra) hard and veinless, meeting in centre line

Go to 10

Forewings with many veins, overlapping at least a little and often held roofwise over the body

 

Go to 11

10

Abdomen ending in a pair of forceps : elytra always short

Dermaptera

Abdomen without forceps: elytra commonly cover whole abdomen

 

Coleoptera

11

Insects with peircing and sucking beaks

Hemiptera

Insects with chewing mouthparts: cerci (‘tails’) usually present

 

Go to 12

12

Hind legs modified for jumping

Orthoptera

Hind legs not modified for jumping

 

Dictyoptera

13

Tiny insects covered with white powder

Go to 14

Insects not like this

 

Go to 15

14

Wings held flat at rest: mouth-parts adapted for piercing and sucking

Hemiptera

Wings held roofwise over body at rest: biting mouthparts

Neuroptera

15

Small, slender insects with narrow, hair-fringed wings: often found in flowers

Thysanoptera

Insects not like this

 

Go to 16

16

Head extending downwards into a beak

Mecoptera

No such beak

 

Go to 17

17

Wings more or less covered scales: coiled proboscis (tongue) usually present

Lepidoptera

Wings usually transparent although often hairy

 

Go to 18

18

Wings with a network of veins, including many cross veins

Go to 19

Wings with relatively few cross veins

 

Go to 23

19

Abdomen with long terminal threads

Go to 20

Terminal appendages short or absent

 

Go to 21

20

Forewings 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

21

Antennae very short: body at least 25mm long

Odonata

Antennae longer: greater than width of head

 

Go to 22

22

Tarsi 3-segmented

Plecoptera

Tarsi 5-segmented

 

Neuroptera

23

Wings noticeably hairy

Go to 24

Wings not noticeably hairy

 

Go to 25

24

All of wings more or less alike: front tarsi swollen

Embioptera

Hind wings usually broader than forewings: front tarsi not swollen

 

Trichoptera

25

Tarsi with 4 or 5 segments

Go to 26

Tarsi with 1 – 3 segments

 

Go to 27

26

All wings alike

Isoptera

Hind wings much smaller than forewings

 

Hymenoptera

27

Hind wings similar to or larger than forewings: abdomen with cerci

Plecoptera

Hindwings smaller than forewings: no cerci

 

Go to 28

28

Tiny insects with at least 12 antennal segments

Psocoptera

Never more than 10 antennal segments: piercing and sucking beak present

 

Hemiptera

29

Insects with slender, twig like body

Phasmida

Insects not like this

 

Go to 30

30

Insects with grasshopper-like body and long back legs

Orthoptera

Insects not like this

 

Go to 31

31

Small, soft-bodied insects living on plants, often under protective sheild or scale

Hemiptera

Insects not like this

 

Go to 32

32

Minute soil-living insects, <2mm long without antennae

Protura

Insects not like this

 

Go to 33

33

Insects with cerci or other abdominal appendages

Go to 34

Insects with other appendages

 

Go to 41

34

Abdominal appendages long and conspicious

Go to 35

Abdominal appendages short or hidden under body

 

Go to 38

35

Abdominal appendages forming pincers

Go to 36

Abdominal appendages not forming pincers

 

Go to 37

36

Tarsi 3-segmented

Dermaptera

Tarsi 1-segmented

 

Diplura

37

Abdomen with 3 long terminal appendages

Thysanura

Abdomen with only 2 terminal appendages

 

Diplura

38

Tiny jumping insects, head points downwards forming a beak

Mecoptera

No sign of beak

 

Go to 39

39

Small or minute insects with a forked springin organ under rear of abdomen: generally found in soilor decaying vegetation

Collembola

Insects not like this

 

Go to 40

40

Tarsi usually 4-segmented

Isoptera

Tarsi 3-segmented: front tarsi swollen

 

Embioptera

41

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

42

Jumping insects flattened from side-to-side

Siphonaptera

Insects flattened dorso-latterally

 

Go to 43

43

Insects of moderate size: head partly withdrawn into thorax

Go to 44

Small minute insects: head not withdrawn into thorax

 

Go to 45

44

Antennae very short: very ‘leggy’ insectswith strong claws well suited to clinging to a host mammal

Diptera

Antennae long: body somewhat circular, with less prominant legs and claws

 

Hemiptera

45

Prothorax distinct: biting mouths

Mallophaga

Thoracic segments fused into one unit: sucking mouths

 

Anoplura

46

Abdomen with pronounced ‘waist’: antennae often elbowed

Hymenoptera

No such features

 

Go to 47

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

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 near hind end: insects found on growing plants

 

Hemiptera