This group has been fairly consistently placed in a steingeliine family group taxon. There is considerable variation in characters such as the number of setae on the legs, but the 2 included genera seem to form a distinct group. Steingeliidae Morrison was first treated as a family by Koteja (1989b).
Steingelia is probably restricted to Betula and Stomacoccus feeds on Platanus.
Stomacoccus platani Ferris has at least 3 instars in the female and there are 5 in the male. Adults overwinter on the bark and migrate to the leaves in the spring. There are as many as 9 generations a year. Steingelia gorodetskia Nassonov has 4 instars in the female and 5 in the male. Most feeding occurs in the second and third instarcysts which are located on main roots underground or deep in bark cracks. Adult females emerge from the third-instar female and move onto the trunks of trees. After mating, adult females produce an ovisac and lay eggs. Crawlers move back to the main roots. There is 1 generation per year.