1974 ] 
Brown — Ant Genus Proceratium 
73 
taken in side view from the dorsal side of the juncture with the post- 
petiole straight to the most posterior part of the curve of the second 
(downcurved) gastric segment (true abdominal segment IV). 
Paratype workers (19 measured from 3 colonies at the type local- 
ity) : TL 4. 7-5.0, HL 0.92-0.98, HW 0.91-0.98 (Cl 96-101), ML 
0.31-0.34, scape L 0.90-0.99, greatest diameter of eye close to 0.09, 
WL 1.38-1.49, L petiole in side view 0.59-0.61, L petiolar node 
0.42-0.47, W petiolar node 0.41-0.47, L hind tibia 0.96-1.02, L hind 
metatarsus 0.80-0.87 mm. 
Composite description: Form of head and body more or less as 
shown in Figs. 1 and 2. Variation occurs in the following traits: 
Posterior border of head in full-face view varying from transverse, 
nearly straight (holotype) to broadly rounded with or without a 
narrow flattened or even feebly concave median portion, as in Fig. 2. 
Nuchal carina (on cervical face of head) continuing as a ventro- 
lateral margin halfway down each side of head. Sides of head vary- 
ing from approximately straight and parallel (Fig. 2) to gently con- 
vex and slightly converging anteriad. Eyes each composed of a single 
clear, convex facet. Median lobe of clypeus with sides feebly sinuous, 
as in Fig. 2, or merely weakly convex. Mandibles with 4 strong 
teeth, but one of these is sometimes double; in addition a small offset 
tooth is sometimes developed at the basal angle, normally hidden when 
closure is complete. The inner margin of the peduncle of the mandi- 
ble has a low, suboblong, sinuous or even bidentate ridge or lamella, 
visible only when the mandible is open. The scapes vary in length 
and slightly in apical thickness, so that when laid straight back they 
surpass the posterior border of the head by amounts ranging from less 
than half their apical thickness to more than their apical thickness. 
Labral shield bilobate, the lobes separated by a broad V-shaped 
notch; also, lateral to each lobe is a small thumb-shaped lobe or knob 
extending dorsomesally (flexad) of the plane of the shield from its 
basal ridge. Maxillary palpi 4-segmented, the basal segment short and 
cylindrical, the second segment flat and attached to the basal segment 
at nearly a right angle by a peduncle that arises from the side of II; 
III and IV are short elliptical segments extending in line from II. 
This is the characteristic form of maxillary palpi in Proceratium , 
Labial palpi 3-segmented. 
Trunk convex from side to side, and from front to rear in side 
view, but the portion of the outline from mesonotum to propodeal 
declivity may be straight or may be interrupted by a feeble dip or 
saddle in the region of the obsolete metanotal groove. The propodeal 
