Slide showing hierarchical diagram of 'Cross between 'ebony' and 'vestigal' mutants of the banana fly'. Slide shows hierarchical diagram of 'Cross between 'ebony' and 'vestigal' mutants of the banana fly'. Images consist of the two flies and the mutants descended from them. Title below image reads: 'Fig. 84 - Cross between 'ebony' and 'vestigal' mutants of the banana fly'. Late 19th century to early 20th century