Development of the California red scale. Until the first molt ends, development of the female and male scales is the same. During the middle of the second instar, the female extends its round gray margin, Whereas the male develops an elongated cover. The females molt once more, the males three more times. After the second molt, the female incorporates the cast skin into the gray margin of the previous stage and begins to extend the margin further. The third instar male begins to develop eye spots and appendages; and in the fourth instar, the male appendages are completely developed (the scale cover is removed to reveal the third and fourth instars as illustrated). After the fourth molt, the two-winged adult male emerges. By this time, the adult virgin female has extended its margin and is ready to be fertilized by the emerging male. The gravid female extends its margin further to reach the full size of the reproducing female. (The illustrated reproducing female is turned over to show body with posterior lobes filling the scale cover.)

Illustration from Integrated Pest Management for Citrus, 1st edition. UC ANR Publication 3303.