costal vein fly_anatomy.ontology Vein that follows the full length of the anterior edge of the wing blade (Stark et al., 1999; Blair, 2007). Its longest (distal) segment is contiguous with wing vein L1 (Blair, 2007). FBbt:00004755 https://www.ento.csiro.au/biology/drosophila/melanogaster.html?C costa The distal costa is sometimes also referred to as marginal vein or wing vein L1 (Blair, 2007). marginal vein longitudinal vein