Longitudinal veins fused at base of wing into bifid stalk. L3 delta-like at tip; L4 often incomplete at tip. Wing margins often excised at tip of L4. Wings spread in proportion to their shortness. Phenotype like bi1, but males show 100% expression at 25oC and females show 0-3%. RK1 in male RK3 in female.
Gottschewski, 1935.