1. Orders of Aquatic Insects

2. Classification

3. Known Living Species = 1,830,725

4. Collembola (“Springtails”)
Larva and Adult:
Eyespots
Segmented legs
Abdominal tube (Collophore)
Abdominal furca (“spring”)

5. Ephemeroptera (“maylfies”)
Larva:
Segmented legs
Compound eyes
2-3 “tails”
Gills on abdomen
Subimago
Dull appearance
Imago (Adult):
Antennae inconspicuous
Hindwings small
2-3 tails

6. Odonata (“dragonflies” and “damselflies”)
Larva
Segmented legs
Compound eyes
Hinged labium
3 terminal plate-like gills or none
Adult
Antennae inconspicuous
Wings equally long, held above or beside body
Abdomen long, slender

7. Plecoptera (‘stoneflies”)
Larva:
Segmented legs
Compound eyes
2 “tails”
Gills filamentous, thoracic, if present
Adult:
Antennae long
Wings equally long, folded over abdomen, hind wings folded
Cerci usually long

8. Orthoptera (“grasshoppers”)
Larva and Adult:
Conspicuous antennae
Hind femora large

9. Blattodea Oval body Head hidden in dorsal view
Cursorial legs with 5-segmented tarsi
Wings present, sometimes reduced esp.in ♀♀

10. Hemiptera-Heteroptera (‘bugs”)
Larva:
Similar to adult
Adult:
Antennae conspicuous or hidden
Beak-like mouthparts
Bases of adult forewings leathery

11. Megaloptera (“hellgrammites/dobsonflies” and “alderflies”)
Larva:
Eyespots (stemmata)
Segmented legs
7-8 pairs of abdominal filaments
2 pairs anal hooks OR
caudal filament
Pupa:
Terrestrial
Adult:
Antennae conspicuous
Many crossveins along forewing front margins

12. Neuroptera (“spongillaflies”)
Larva:
Eyespots (stemmata)
Style-like mandibles
Pupa:
Terrestrial in double cocoon
Adult:
Megaloptera-like
Small mandibles

13. Trichoptera (“caddisflies”)
Larva:
Eyespots (stemmata)
Antennae inconspicuous
Segmented legs
1 pair anal hooks
Pupa:
Large mandibles
Adult:
Long antennae and palps
Hairy wings held roof-like

14. Lepidoptera (“caterpillars/moths”)
Larva:
Eyespots (stemmata)
Segmented legs
With or without gills
In plants
Pupa:
Adult:
Coiled proboscis
Colorful, scaly wings

15. Coleoptera (“beetles”)
Larva:
Eyespots (stemmata)
Segmented legs
No anal hooks OR four hooks OR 2 hooks with hard covering
Pupa:
Terrestrial
Adult:
Antennae short or long
Hard elytra

16. Diptera (“flies”) Larva: Pupa: Adult: Head conspicuous or not
No segmented legs
Pupa:
Prothoracic spiracular gills (“horns”)
Adult:
1 pair of wings
1 pair of halters

17. Hymenoptera (“wasps”)
Larva:
Eyes/antennae inconspicuous
Thorax indistinguishable
No segmented legs
Pupa:
In host
Adult:
Conspicuous antennae
Wings transparent
Hind wings smaller than forewings

18. Known living aquatic insect species = 103,225

19. Larval Identification
Mature larvae are best
Hand lens with 10–20X for family
Microscope with at least 50X for genus/species
2 pairs of very fine lab forceps
Specimen fully submerged in alcohol
Less than 50% of Nearctic species identifiable -- a serious research need!

21. Relatively Low Tolerance Values NCBI (Lenat 1993)
Plecoptera: (0.0–6.3)
Trichoptera: (0.0–8.1)
Ephemeroptera: (0.0–9.3)
Coleoptera: (0.0–10.0)
Dip.-Chironomidae (0.0–10.0)
Megaloptera: (5.5–7.5)
Other Diptera (0.2–10.0)
Odonata: (1.6–10.0)