in 1910, the common fruit fly, drosophila melanogaster, became a model organism in genetics due to the pioneering experiments of thomas hunt morgan. in 1923, bridges and morgan published much of their data on genetic experiments in carnegie institution publ. no. 327. among the experiments they reported in this volume concerned two characteristics: wing position and scutellar hair. normal (wild-type) flies fold their wings over their abdomens when at rest but flies w