Mycocepurus tardus Weber

Kempf, W. W., 1963, A review of the ant genus Mycocepurus Forel, 1893 (Hymenoptera: Formicidae)., Studia Entomologica (N. S.) 6, pp. 417-432 : 430-431

Mycocepurus tardus Weber

Mycocepurus tardus Weber , 1940: 416-417. fig. 13 (Worker; Panama Canal Zone: Rarro Colorado Island).

Worker (lectotype). - Total length 2.9 (3.1) mm; head length 0.68 (0.71) min; head width 0.64 (0.68) mm; scape length 0.56 (0.56.) mm; thorax length 0.88 (0.93) mm; hind femur length 0.67 (0.69) mm.. Reddish-brown; opaque.

Resembling quite closely smithi in general habitus and sculpture, presenting the following differences: Occipital teeth quite prominent. Base of scape obliquely truncate in front of articular condyle, laterally and ventrally with a prominent carinule around base (incomplete ring). Promesonotum with a prominent pair of teeth in the middle of the circlet; infero-lateral tooth of pronotum small but distinct. Anterior pair of posterior mesonotal teeth practically absent, of epinotal teeth extremely low and blunt; connecting longitudinal carinules between posterior mesonotal and epinotal teeth absent or only vestigial. Clypeus and dorsum of scapes with erect hairs; tibiae and dorsum of gaster with curved not quite appressed hairs.

This species is known only from Barro Coliorado Island, Panama Canal Zone.

Specimens examined: Barro Colorado Island, Panama C. Z., June 12, 1938, N. A. Weber leg. n. 749, 1 worker (lectotype); same locality, N. A. Weber leg. June 1956, 1 worker (both in WWK received from NAW).

Discussion. - M. tardus combines with the general fades of smithi a few characters of goeldii (spinulation of premesonotal disc, pilosity of clypeus and scape), but seems for the time being sufficiently distinct from both. Weber (1940, fig. 13) gives a good lateral view of the thorax.

Note. - I have another worker from Barro Colorado Island (NAW n. 3805) which represents still another smithi-like variant, lacking completely the pair of anterior mid-pronotal teeth, a feature not observed in any other Mycocepurus specimen; its postpetiole is distinctly broader than long. Whether or not it is a still imdescribed species may not be decided for the time being.