Tapinoma

Genus Tapinoma Forster, 1850

Tapinoma Förster, 1850:43.

Type-species: Formica erratica Latreille, 1798.

Workers monomorphic but size in some species variable. Antennae 12 segmented; palp formula 6, 4. Clypeus with front border truncate or incised. Petiole a small inconspicuous node overhung by the first gastral tergite. Queens as workers but with enlarged flattened alitrunk. Males have filiform thirteen segmented antennae with long scapes overreaching the occipital border. Head large relative to alitrunk. Genital armature with large prominent stipes.

This is a world-wide genus with most species found in the Indo-Australian and Ethiopian regions. There are several palaearctic species of which only one is indigenous north of latitude 50°. One or more of the smaller tropical species are cosmopolitan and sometimes establish in heated premises.

Keys to species of Tapinoma

Queens and workers

1 Median portion of anterior margin of clypeus incised; colour evenly dark brown to black............................................................................. 2. erraticum (Latreille)

- Median portion of anterior margin of clypeus entire; bicoloured with dark head and promesonotum contrasting with pale gaster, propodeum and appendages melanocephalum (Fabricius)

Males

1 Appendages and part of gaster very pale; length less than 2.5 mm melanocephalum (Fabricius)

- Appendages and gaster unicolorous dark with rest of body; length 3.5 mm or greater............................................................................... 2. erraticum (Latreille)