Slide showing four sets of diagrams relating to chromosomes of drosophila melanogaster (type of fruitfly). Slide shows four sets of diagrams relating to chromosomes of drosophila melanogaster (type of fruitfly). Four diagrams have various labelling with some explanation below. Title below images reads: 'Fig 62 - left: comparative linkage maps of the right arms of the third chromosome in drosophila melanogaster and drosophila simulans (Sturtevant, 1929). Right: pairing of these chromosomes in the salivary gland of the hybrid between the species. Above: the two fourth chromosomes of the species. Below: mitotic chromosomes of drosophila melanogaster, [male ]. (Patau, 1935.)' Late 19th to early 20th century