A chromosomal survey of 140 species of 73 genera of armored and palm scale insects revealed the distribution of the 3 chromosome systems (Iecanoid, Comstockiella, and diaspidid), of parthenogenesis, and of variation in chromosome number among the subdivisions of this section of the coccids, the Diaspidoïdae.

The heterochromatic Comstockiella system, with which the Iecanoid system is usually associated, is the basic system of the section and is found in all the tribes for which sexual forms are known, as well as in the palm scales, however defined. The heterochromatic Iecanoid system has been found only once by itself, in a species of palm scale. The diaspidid system is restricted to the two major tribes of the armored scales, the Diaspidini and Aspidiotini, where it has been found in the majority of forms.

Parthenogenesis is widespread, and unisexual strains have been newly discovered in several species previously considered sexual. Contrary to what might be expected, there is little variation in chromosome number in the parthenogenetic forms.

The basic haploid chromosome numbers are 5 for the palm scales (restricted sense) and 4 for the armored scales. A somewhat higher basic number may exist for the nude forms, such as Phoenicococcus marlatti (excluded here from the palm scales in the restricted sense) and Xanthophthalma concinnum. Chromosome numbers range from 3 to 9; there is considerably more variation in chromosome number in the Diaspidini than in the Aspidiotini. In the latter tribe, however, the Comstockiella chromosome system may be playing a more active role in evolution than in the former.

In addition, various cytological aspects, ranging from details of spermiogenesis to the formation of chromocenters in mycetocytes, have been described for certain species.