342 
Psyche 
[December 
laraka, on the eastern side of the Baie d’Antongil, Province de 
Tamatave, Malagasy Republic, on 26 November 1969, by J. -M. 
Betsch. 
This altogether extraordinary ant is distinguished at once from its 
congeners by the strongly produced and downcurved “false apex” of 
the second gastric segment, as well as by the form of the propodeum, 
and several minor characters of sculpture, etc. It is the first species of 
its genus to be taken on Madagascar, and its must be placed in a 
species group of its own. Its relatively large size, large but single- 
facetted eyes, elongate petiole, coarse sculpture and developed pro- 
podeal teeth ally it with the stictum group of primitive species more 
closely than any other group. 
Proceratium micrommatum (Roger) 
(=P. convexiceps Borgmeier) new synonym 
Earlier (Brown 1974:82) I called attention to the doubtful status of 
P. convexiceps Borgmeier (1957:120-122, fig. 34). Not only do sam¬ 
ples 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 dif¬ 
ferences. 
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. 
Key to New World Proceratium, Workers 
1. Petiolar node in the form of a thick, erect scale with nearly 
parallel anterior and posterior faces (posterior face may be con¬ 
cave), apex truncate or subtruncate in side view; second gastric 
(IV true abdominal) segment curved downward, but neither 
