| 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. |

