1965] 
Ettershank — Megalomyrmex 
57 
= 2 3 (22, 21). A fourth paratype worker was dissected and not 
measured. 
This species is smaller than the other goeldii group species. The 
head (fig. 1) in dorsal view is rather more square in shape. The eyes 
are large, about 15 ommatidia high and 8 wide, and their black color 
contrasts strongly with the golden-brown ground color of the head. 
Antennae 12-segmented with a weak 3-segmented club (fig. 2). 
Clypeus strongly convex with a slight median sulcus, giving a weakly 
bicarinate effect. Median seta present, but variable in position around 
the midpoint of the oral margin of the clypeus ; one pair of intercarinal 
setae present ; first paracarinal setae well developed, higher paracarinal 
setae weaker. A few strong lateral setae present. Lateral areas of 
clypeus and oral margin of median area concolorous with mandibles. 
Mandibles with dental formula 1 + 4, masticatory margin more 
darkly colored, brown black, rest of mandible red-brown. Palpal 
formula 4, 3. 
Alitrunk (fig. 3) of normal worker form. Promesonotal suture 
very distinct on the pleurae to the height of the spiracle, curving 
forward and then posteriorly; indistinct laterally above the spiracle 
and on the dorsum. Metanotal groove distinct, impressed on the 
dorsum and on the pleurae. Faint grooves separate the anepisternum 
from the notum above and the katepisternum below. Mesothoracic 
dorsum narrowing rapidly above, quite distinctly compressed at the 
metathoracic groove. Propodeum with angle distinct but rounded; 
declivity distinctly impressed. Propodeal spiracle small, round. 
Inferior propodeal plate's large, semicircular. Metapleural glands 
large, very distinct, surmounted postero-ventrally by a rounded 
protuberance bearing the gland opening. 
Petiole and postpetiole of normal Megalomyrmex form, with nodes 
high and rounded (see fig. 3). Subpetiolar process dentiform, distinct; 
anterior subpostpetiolar process distinct, posterior process slight ; nodes 
not particularly broad above. Gaster biconvex in profile, attached at 
its most anterior end, in life normally carried with its long axis 
inclined downward so that the posterior end just clears the substrate. 
Smooth shining ants, bearing a few faint and several distinct rugae 
on the mesokatepisternum and metapleuron. Posterodorsal flange of 
the postpetiole finely granulose. Head, alitrunk and gaster bearing 
sparse, long, white setae. Head (except as noted earlier), alitrunk, 
Explanation of Plate 4 
Megalomyrmex bicolor, n. sp., Worker: Fig. 1, head, dorsal full-face 
view. Fig. 2, antenna. Fig. 3, alitrunk and nodes, lateral view. Larva: 
Fig. 4, lateral profile. Fig. 5, setae (see discussion in text) ; a, dorsal and 
lateral abdominal; b, of head and prothorax; c, of ventral abdominal tufts. 
