Appearance of distal extra longitudinal veins preferentially associated with plexi between LII and LIII on one side and between LIV and LV on the other.
Rank: RK1 Phenotype of homozygotes is similar to that of net3 and milder than that of net1 flies. No blistering of the wings is seen in net4 homozygotes.
"spontaneous" was stated as tentative. "X ray" was stated as tentative.