Slide showing diagram of 'A comparison of the gene arrangements in Drosophila pseudo-obscura and D. miranda.' Slide shows black and white diagram of 'A comparison of the gene arrangements in Drosophila pseudo-obscura and D. miranda.' These are various species of fruit fly. Title below image reads: 'Fig. 13 - A comparison of the gene arrangements in Drosophila pseudo-obscura and D. miranda. Sections having the same gene arrangements in the two species are white; inverted sections, cross-hatched; trans-locations, stippled; sections of which the homologues are not detectable in the other species, black.' Late 19th to early 20th century