Slide showing a chart demonstrating 'changes in the rate of reproduction of Drosophila [fruit fly] with increasing density of mated population'. Slide shows a chart demonstrating 'changes in the rate of reproduction of Drosophila with increasing density of mated population'. X axis is entitled 'mean flies per bottle' and the scale is from 0 to 90. Y axis is entitled 'progeny per female day', and the scale is from 0 to 22. Title below image reads: 'Fig 27. Showing changes in rate of reproduction of Drosophila with increasing density of mated population. The circles give the observations and the smooth curve is the graph of the logarithmic equation discussed in the text.' Late 19th to early 20th century