Relative timing of appearance of primary double eve1 stripes, intercalating eve1 stripes, and morphological segments. The plot shows the correlation among the appearance of morphological segments (blue), intercalated eve1 stripes marking single segment periodicity (red) and primary eve1 stripes of double segment periodicity (yellow). Each position along the X axis represents a single embryo from one of eight clutches (A-H, individual embryos numbered), ordered by the developmental age of each embryo, as defined by these markers. The location of the markers on one embryo (B15) is illustrated in the inset. The Y axis plots the number of leg-bearing segments (blue points) or the LBS number that each eve1 stripe will eventually correspond to (red and yellow points). The numbering of primary stripes has been subdivided to indicate the extent of stripe resolution. For example, the embryos illustrated in Figure 4, panels A3, B3, C3, D3, which show the progressive resolution of primary stripe 28, would be assigned the values 26.0, 26.4 (the onset of cycle 28), 26.6 and 26.8. Developmental stages (stages 2.3 to 5), shown in schematic form below the plot, are delimited by vertical lines.