Fig. 1. The wing phenotype of dve^P1738-mutant flies. All wings are oriented proximal to the left and anterior to the top. (A) A wild-type wing. The arrowheads highlight the distance between the end of the medial costa and the anterior cross-vein. The longitudinal veins are numbered 2-5. The arrow indicates a small spot of vein material present in the proximal part of the wing blade. (B) A dve^P1738-mutant wing. The arrows indicate regions where the longitudinal veins 2 and 5 are interrupted. Note that the distance between the arrowhead in the PW and that at the anterior cross-vein is strongly reduced in comparison with the normal wing. Furthermore, the wing is smaller than the wild-type wing. (C) A magnification of the PW of a wild-type wing. The anterior margin of the PW is subdivided into three easily distinguishable regions: the proximal, medial and distal costa. (D) The PW of a dve^P1738-mutant wing. Most of the distal costa is deleted leaving only a very small remnant intact. Furthermore, the small spot of vein material, which can be observed in the adjacent wing blade (highlighted by the arrow in A and C), is deleted in the mutant wing, indicating that a small stripe of the adjacent wing pouch is also deleted. These observations indicate that Dve is required for the formation of a region encompassing most of the distal PW and a small part of the adjacent pouch. This region is highlighted by the pink box in A. The deletion causes the reduction of the distance between the anterior cross-vein and the PW.