Medius anterior: Vein MA is the anterior fork of the media, which is the “fourth” major longitudinal wing vein in insects. However, in mayfly forewings, the two forks often appear to be separate veins all the way to the wing base, and MA sometimes appears to branch from Rs near its base. Vein MA itself usually forks into an anterior fork MA1 and a posterior fork MA2. Usually, MA can be quickly located in mayfly forewings by looking for the vein that splits the wing in half length-wise and forks in two somewhere around 2/3 of the way from the base to the tip. MA and its forks are ridge veins (+).
These other words reference the same concept: media anterior, vein MA, MA vein, MA, vein MA1, MA1 vein, MA1, vein MA2, MA2 vein, MA2.
