Calvin Bridges is, with Alfred Sturtevant, one of my heroes of Drosophila genetics. Among his achievements were the demonstration and confirmation of the chromsome theory of inheritance, and the establishment of the polytene chromosome maps (for more about polytene chromosomes, see this article). Bridges was one of the early members of the Morgan fly lab, and stayed there for his entire (though unfortunately short) career. Kohler, in his excellent history of Drosophila genetics, characterises Bridges as the "blue collar" member of the lab, the worker who would invest huge energy in the technical development of Drosophila genetics.
