Fly Tier’s Entomology Glossary

Abdomen That portion of an insect’s body located between the thorax (legged portion) and tail; various filaments, hairs, and plate like or filamentous gills may be attached to the abdominal segments, but not legs. [See also Body.]
Attractor fly A fly that does not imitate a specific insect, but that attracts a fish for reasons other than its matching the hatch (such as Royal Coachman, Humpies, Wulffs, Bivisibles, and the like).
Bass bug A fairly bulky floating artificial lure used in fly-rodding for bass, panfish, and certain other fish, including large trout. May be an attractor pattern, or may imitate a dragonfly, damselfly, grasshopper, other large aquatic or terrestrial insect, mouse, frog, salamander, or the like.
Body Insect’s thorax and abdomen, collectively; as used by fly tier’s, refers principally to the abdomen, the thorax’s appearance being suggested by the hackle.
Caddisflies Aquatic insects of the order Trichoptera.
Damselflies Aquatic insects of the suborder Zygoptera (order Odonata), whose wings are usually held above the body at rest; larval forms (nymphs) frequently used for trout, bass, sunfish.
Downwings Collective term for caddisflies, stoneflies, and midges.
Dragonflies Aquatic insects of the order Odonata (and sometimes particularly of the suborder Anisoptera, whose wings are outspread laterally from the body when at rest); larvae have provided numerous important nymph patterns.
Dry fly Floating insect imitation, often of the adult (image) form; in mayfly imitations, may be tied as a dun or spinner.
Dun The subimago (subadult) emergent mayfly form during metamorphosis.
Flatwings Stoneflies.
Half-spent Descriptive of late adult stage, during or immediately after deposition of eggs.
Imago Sexually mature, adult stage of insect following metamorphosis.
Midges Tiny aquatic insects belonging to the family Chironomidae (although flies imitating other members of the order Diptera are sometimes also called midges).
Mayflies Aquatic insects of the order Ephemeroptera, which account for most of the important hatches; tied and fished as nymphs, duns, and spinners.
Nymph (1) The larval, pupal, or nymphalstageearly in an insect’s development; (2) a wingless, sinking fly tied to imitate it or other wingless aquatic creatures, for instance, scuds.
Pupa Development stage immediately preceding adult stages in insects with complete metamorphosis.
Scuds Any of several freshwater crustaceans of the order Amphipoda, which are important fish foods and have supplied numerous nymph patterns.
Sowbugs Freshwater crustaceans of the order Isopoda, sometimes used to pattern flies for nymph fishing.
Spent Descriptive of late adult stage, abler eggs have been deposited.
Spinner Adult or image stage in mayfly development.
Stoneflies Aquatic insects of the order Plecoptera, tied and fished as nymphs and wet and dry flies.
Subimago Winged, subadult (dun) stage in mayfly development.
Tentwings Caddisflies.
Terrestrial Short for “terrestrial insect”; fly tied to imitate a terrestrial or nonaquatic insect, such as ant, bee, beetle, cricket, grasshopper, and so on.
Thorax Portion of an insect’s body between the head and abdomen; the six legs are attached to the thorax.
Trico Abbreviated form of Tr~chorythodes, an important genus of small mayflies often called tiny whitewinged blacks.
Upwings Mayflies.
Water bugs Aquatic insects belonging to the order Hemiptera, including backswimmers, water boatmen, water striders, and the like; wet flies imitating them are of local or limited angling importance.
Wet fly Imitation insect tied so that it will sink in the water; may imitate nymphal, preemergent, or spent adult form.