Slide showing a table demonstrating 'effect of larvae history before use'. Slide shows a table demonstrating 'effect of larvae history before use'. Title above table reads: 'Effect of larvae history before use', and the date '23.7.39' appears in the upper right corner. Table has six columns. First column is untitled, but shows location of the larvae. Second column is labelled 'Ant.' (there are two small circles below this). There are two sets of numbers set out in two further columns. The third column is similarly divided but labelled '1/2 Ant.' Fourth column is labelled 'Vt.' (with two split columns below that). The last two columns are labelled with the greek letters, alpha and beta, each with one set of figures. Below the table, title reads: 'larvae collected on either Pearl or Cornmeal agar and transferred to 24 hour'. Late 19th century to early 20th century