Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Media: The media (denoted M) is the fourth major longitudinal wing vein in insects, located behind the radial sector. In caddisflies, it splits into anterior branch MA (sometimes called M1+2) and posterior branch MP (sometimes called M3+4). In both wings, MA splits into an anterior branch M1 and posterior branch M2. In caddisfly forewings, MP typically splits into M3 and M4, but it does not split in hind wings.
These other words reference the same concept: vein M, M vein, M, M1, vein M1, M1 vein, M2, vein M2, M2 vein, M3, vein M3, M3 vein, M4, vein M4, M4 vein, M1+2, vein M1+2, M1+2 vein, M3+4, vein M3+4, M3+4 vein, vein MA, MA vein, MA, vein.
The specimen illustrated here is unusual in that M3+4 barely forks in the forewings, and that it forks at all in the hind wings.
