Earlier (Brown 1974:82) I called attention to the doubtful status of P. convexiceps Borgmeier (1957:120-122, fig. 34). Not only do samples of this complex (including new collections from Honduras: Lancetilla, near Tela; and 14 km S. La Ceiba; both in rotten logs, W. L. Brown, Jr.) vary in the development of the median clypeal process, which may be absent, weakly projecting, or strong, but it seems clear that the "Arbeiter" of micrommatum against which Borgmeier (1957:118-120) compared convexiceps was actually an ergatoid queen of micrommatum , so that differences in head shape, eye size and petiolar thickness are apparently only allometric caste differences.
A worker specimen of P. micrommatum from Honduras was dissected and proved to have maxillary palpi of 3 segments, the second segment having the "hammer-head" form characteristic of Proceratium , i.e., it is stalked from the side, and the apical segment has 3 long apical sensilla. Labial palpi with each 2 segments: basal segment narrower, apical segment claviform, with 3 long apical sensilla.
