Identification of orders of aquatic insects

TerminologyDiagram on page 54Glossary on pages 179-

185

Compound eye

Antenna

Labrum

Wing pads

Femur

Tibia

Metanotum

Gills

Cercus

Mesonotum

Pronotum

Tarsus

Claw

Abdomen

Ward et al.’s key to orders

EphemeropteraMayfliesAll larvae aquaticCharacteristics

Wing pads1 claw on each leg

(contrast with Plecoptera)2-3 terminal segmented

filaments (cerci) on abdomen

Usually with lateral abdominal gills

PlecopteraStonefliesAll larvae aquaticCharacteristics

Wing pads2 claws on each leg

(contrast with Ephemeroptera)

2 cerciNo lateral abdominal

gills

TrichopteraCaddisfliesAll larvae aquaticCharacteristics

No wing pads (contrast with Ephemeroptera and Plecoptera)

3 pairs of jointed legs on thorax (contrast with Diptera)

1 pair of terminal abdominal prolegs (contrast with Lepidoptera and larval Coleoptera)

Often in cases

DipteraTrue fliesAll larvae aquaticCharacteristics

No jointed legs on thorax, some with prolegs on prothorax (contrast with Trichoptera, larval Coleoptera and Lepidoptera)

Very diverse group

What are these taxa?

Chironomidae

ColeopteraBeetlesSome adults and larvae

aquaticMostly lentic except for

ElmidaeCharacteristics

Adults 1st pair of wings hardened

to form nonoverlapping shell-like covering (elytra) over abdomen (contrast with adult Hemiptera)

Chewing mouthparts

ColeopteraCharacteristics

Larvae 3 pairs of jointed legs on

thorax (contrast with Diptera)

No terminal abdominal prolegs (contrast with Trichoptera)

OdonataDragonflies and damselfliesAll larvae aquatic

Mostly lenticCharacteristics

Wing padsNo cerci, some with

unsegmented terminal gills (contrast with Ephemeroptera and Plecoptera)

Grasping mouthparts forming hinged structure (labium) under head (contrast with larval Hemiptera)

HemipteraTrue bugsSome adults and larvae aquatic

or semi-aquaticMostly lentic except for

NaucoridaeCharacteristics

1st pair of wings with hardened base and overlapping membranous apical portion (contrast with adult Coleoptera)

Sucking/piercing mouthparts forming long jointed beak (contrast with larval Coleoptera and Odonata)

LepidopteraButterflies and mothsFew larvae aquatic

Mostly lentic except for Pyralidae

Characteristics3 pairs of jointed legs on

thorax (contrast with Diptera)

At least 2 pairs of abdominal prolegs terminating in circle of hooklets (crochets) (contrast with Trichoptera and larval Coleoptera)

MegalopteraDobsonflies and alderfliesAll larvae aquatic

Mostly lenticCharacteristics

7-8 pairs of lateral abdominal filaments (contrast with Trichoptera and larval Coleoptera)

Sialidae with long pointed filament at apex of abdomen

Corydalidae with anal hooks on final abdominal segment