Dr. K Toyama and Mendel's laws of inheritance.
Like drosophila, silkworms have been a good subject for genetic research since they breed quickly if you get the conditions right. Consequently, it was Dr. K Toyama's experiments on silkworms in 1902 which first demonstrated that Mendel's newly rediscovered laws on inheritance also applied to animals (as well as plants). It was a controversial finding, apparently, and there is more about it in a paper published last year by L Onaga. It looks very interesting, but unfortunately, since I am not an academic and consequently have no access to a university library, it would cost me $40 to read it. Maybe I'll see if it is possible to take a look next time I'm in the British Library.