Slide showing hierarchical diagram of fruit flies showing 'operation of inheritance involving a deficiency'. Slide shows a hierarchical diagram of fruit flies showing 'operation of inheritance involving a deficiency'. Title at top of slide reads: '1 notch [female]: 1 wild type [female]: 1 wild type [male].' The diagram shows 1 notch 8 female and 1 yellow white facet male and the hybrids achieved from breeding or not: 'wild type female', 'white! facet! Notch 8 female', 'wild type male' and 'dies'.' Title below image reads: 'Figure 88 - Operation of inheritance involving a deficiency. Notch - 8 females, heterozygous for deficiency represented by a blank space in one of the X chromosomes, crossed with yellow-white facet males gives wild type [two females], white facet [two females] and wild type [two males] in approximately equal numbers. The expected notch males die on account of the lethal action of the deficiency. The F1 notch females are white facet because the deficiency covers this section; they are not yellow, because the factor for yellow lies outside the deficient section. Facet, a roughened eye character, is not shown in the diagram. (From Mohr).' Late 19th to early 20th century