Ants in the Formica genus can be further seperated by color, shininess, and presence/absence of silvery sheen.
All black with silvery sheen on body
Formica argentea
Formica subaenescens
Formica subsericea
Shiny brown or reddish brown
small and compact
Formica lasiodes (ant of open habitats)
Formica neogagates (ant of woodlands)
body long
Formica dolosa
Formica pallidefulva
Formica incerta
Red and black with matte apperance
Formica aserva
Formica difficilis
Formica exsectoides
Formica integra
Formica obscuriventris
Formica prociliata
Formica rubicunda
Formica subintegra