Key to adult females of known species of Stigmacoccus

1. Area of sclerotisation present medially on dorsum of head; if absent, then this area with many large spinose pores and derm with a distinct reticulate pattern; tubular pores absent medially on head; thoracic spiracles each surrounded by a group of loculate pores on derm .......................................................... S. asper

- Without an area of sclerotisation medially on dorsum of head; derm in this position without large spinose pores and without a distinct reticulate pattern; tubular pores frequent medially on head; thoracic spiracles either without loculate pores on derm associated with peritreme, or, if present, only between peritreme and margin .................................................................................................................................................. 2

2. With 10-segmented antennae; each loculate pore usually with 1–5 hairs on derm close to pore margin; without a loose group of loculate pores between each thoracic spiracle and margin; without groups of heavily sclerotised loculate pores on walls of vagina ................................................................ S. garmilleri

- With 6- to 9-segmented antennae; loculate pores without hairs on derm close to pore margin; with a loose group of loculate pores between each thoracic spiracle and margin; with groups of heavily sclerotised loculate pores on walls of vagina ................................................................................................ S. paranaensis