A member of the genus Myrmecia in the subfamily Myrmeciinae, it was first described by Austrian entomologist Gustav Mayr in 1862.

The queens are the largest while the males are the smallest, which can be easily identified due to their small mandibles.

Mainly nocturnal M. nigriceps is found in hot hilly areas and woodland, nesting underground in mounds.

The ant's diet consists of sweet liquids from flowering plants and invertebrate prey, which are fed to the carnivorous larvae.

Like other Myrmecia species, M. nigriceps ants possess a powerful and painful sting, and the venom is capable of inducing allergic reactions in sensitive people.

The species was described under the binomial name Myrmecia nigriceps, based on syntype workers collected from Gayndah and Sydney.

[3][4] M. nigriceps was revived as a full species in 1933 by American entomologist William Morton Wheeler, on the basis that it is distributed throughout Australia and its average size is greater than M.

Despite this, it is not known if M. nigriceps is polymorphic, due to little differences in morphology between the workers in comparison to Formicinae ants and Pheidole, with soldiers having enormous heads.

The hairs on males are the longest and most abundant among the worker and queen castes, with a long and broad head.

[11] Myrmecia nigriceps is similar in appearance to M. vindex, but several morphological characters distinguish these two species from each other.

[5][12] The range of M. nigriceps extends from Queensland and down into New South Wales, the Australian Capital Territory and Victoria.

[18] Myrmecia nigriceps ants are crepuscular and nocturnal foragers, searching for food during the night.

[29] With a median lethal dose (LD50) of 7.3 mg/kg, the venom is relatively weak in comparison to other Myrmecia ants, whose LD50 is much lower.

This study also concluded that many other Myrmecia species can cause anaphylaxis, as well as the Green-head ant (Rhytidoponera metallica).