Many thanks to Bob Henricks for compiling this excellent photo reference list
Mayfly (Ephemeroptera)
| Brushlegged (Isonychiidae) | larva | | adult | | other pictures |
| Little Stout Crawler (Leptohyphidae/Tricorythidae) | larva | | adult | | |
| Small Squaregill (Caenidae) | larva | | adult | | other pictures |
| Spiny Crawler (Ephemerellidae) | larva | | adult | | other pictures |
| Flatheaded (Heptageniidae) | larva | | adult | | other pictures |
| Pronggilled (Leptophlebiidae) | larva | | adult | | other pictures |
| Small Minnow (Baetidae) | larva | | adult | | other pictures |
| Ameletid (Ameletidae) | larva | | adult | | other pictures |
| Armored mayfly (Baetiscidae) | larva | | adult | |
| Common Burrower mayfly (Ephemeridae) | larva | | adult | | other pictures |
Stonefly (Plecoptera)
| Roachlike Stone (Peltoperlidae) | larva | | adult | | other pictures |
| Giant (Pteronarcyidae) | larva | | adult | | other pictures |
| Common (Perlidae) | larva | | adult | | other pictures |
| Perlodid (Perlodidae) | larva | | adult | | other pictures |
| Green (Chloroperlidae) | larva | | adult | | other pictures |
| Nemourid (Nemouridae) | larva | | adult | | other pictures |
| Large Winter (Taeniopterygidae) | larva | | adult | | other pictures |
| Small Winter (Capniidae) | larva | | adult | | other pictures |
| Rolledwinged (Leuctridae) | larva | | adult | | other pictures |
Caddisfly (Trichoptera)
| Snailcase Maker (Helicopsychidae) | larva | ||
| Micro Caddisfly (Hydroptilidae) | larva | | adult | |
| Longhorned Case Maker (Leptoceridae) | larva | | adult | | other pictures |
| Lepidostomatid (Lepidostomatidae) | larva | | adult | | |
| Humpless Case Maker (Brachycentridae) | larva | | adult | | other pictures |
| Saddlecase Maker (Glossosomatidae) | larva | | ||
| Uenoid Case Maker (Uenoidae) | larva | | adult | | other pictures |
| Northern Case Maker (Limnephilidae) | larva | | adult | | other pictures |
| Strongcase Maker (Odontoceridae) | larva | | adult | | |
| Giant Case Maker (Phryganeidae) | larva | | adult | | other pictures |
| Common Netspinner (Hydropsychidae) | larva | | adult | | other pictures |
| Fingernet (Philopotamidae) | larva | | adult | | other pictures |
| Trumpetnet (Polycentropodidae) | larva | | adult | | other pictures |
| Freeliving (Rhyacophilidae) | larva | | adult | | other pictures |
Dragonflies, Damselflies (Odonata)
| Clubtail Dragonfly (Gomphidae) | larva | | adult | | other pictures |
| Darner Dragonfly (Aeshnidae) | larva | | adult | | other pictures |
| Skimmer Dragonfly (Libellulidae) | larva | | adult | | other pictures |
| Spiketail Dragonfly (Cordulegastridae) | larva | | adult | | other pictures |
| Broad-wing Damselfly (Calopterygidae) | larva | | adult | | other pictures |
| Spreadwing Damselfly (Lestidae) | larva | | adult | | other pictures |
| Narrow-winged Damselfly (Coenagrionaidae) | larva | | adult | | other pictures |
True Flies (Diptera)
| Net-winged Midges (Blephariceridae) | larva | | adult | |
| Dixid Midges (Dixidae) | larva | | adult | | other pictures |
| Black Flies (Simuliidae) | larva | | adult | | other pictures |
| Midge (Chironomidae) | larva | | adult | | other pictures |
| Biting Midges (Ceratopogonidae) | larva | | adult | | other pictures |
| Crane Flies (Tipulidae) | larva | | adult | | other pictures |
| Soldier Flies (Stratiomyidae) | larva | | adult | | other pictures |
| Horse Flies/ Deer Flies (Tabanidae) | larva | | adult | | other pictures |
| Aquatic Snipe Flies (Athericidae) | larva | | adult | | |
| Dance Flies (Empididae) | larva | | adult | | other pictures |
| Phantom Crane Fly (Ptychopteridae) | larva | | adult | | other pictures |
Beetles (Coleoptera)
| Water Pennies (Psephenidae) | larva | | adult | | other pictures |
| Crawling Water Beetles (Haliplidae) | larva | | adult | | other pictures |
| Riffle Beetles (Elmidae) | larva | | adult | | other pictures |
| Dryopid Beetles (Dryopidae) | larva | | adult | | other pictures |
| Water Scavenger Beetles (Hydrophilidae) | larva | | adult | | other pictures |
| Ptilodactylidae | larva | | adult | | other pictures |
| Predaceous Diving Beetle (Dytiscidae) | larva | | adult | | other pictures |
Aquatic Moth
| Pyralidae | larva | | adult | | other |
Clams (Bivalvia)
| Pea Clam (Sphaeriidae) | adult |
| Asian Clam (Corbiculidae) | adult |
Snails (Gastropoda)
| Pleurocerid (Pleuroceridae) | adult |
| Hydrobiid (Hydrobiidae) | adult |
| Viviparid (Viviparidae) | adult |
| Lymnaeid (Lynmaeidae) | adult |
| Ancylid/Limpet (Ancylidae) | adult |
| Planorbid (Planorbidae) | adult |
| Physid (Physidae) | adult |
Crustaceans
| Sow Bugs (Isopoda) | adult |
| Scuds (Amphipoda) | adult |
| Crayfish (Decapoda) | adult |
More websites with photos and useful info for monitors
- https://bugguide.net
- https://www.pbase.com/tmurray74/bugs
- https://www.troutnut.com/
- https://www.dfg.ca.gov/abl/Reference/California/CA_digital_ref_familylevel_home.asp
- https://watermonitoring.uwex.edu/wav/monitoring
- https://www.waterbugkey.vcsu.edu/. Click on the Order List, then on the picture of the Order. That will take you to an alphabetically arranged list of the Families within that Order.
- https://www.aquatax.ca/TaxaKey.html
- https://www.xerces.org/identification-guides/