Polytene chromosomes normal (J.I. Valencia).
Single gypsy insert in the second intron at a site identical to the gypsy insert of f1.
Larvae exhibit an intermediate bristle phenotype within the denticles of all rows.
"fm" flies (fX Tp(1;1)f+ih double mutant) show a variable phenotype; many have an ordinary f mutant phenotype, but a high percentage show coherent patches of the body, often of considerable size, in which the bristles are normal. Occasionally, almost the whole fly appears wild type.
moderate - both macrochaetae and microchaetae clearly affected A medium f. Suppressed by su(f). hypomorph (Oster, Erlich, and Muller, 1958). RK1. suppressed by su(f) RK1
Muller.
Induced with: Tp(1;1)f+ih.
fX plus Tp(1;1)f+ih denoted "fm: forked-mottled".