1929] The Ant Genera Gesomyrmex and Dimorphomyrmex 
5 
Thorax, petiole, gaster and appendages very minutely and 
sparsely punctate, the gaster also very delicately and in- 
distinctly, transversely coriaceous. 
Hairs yellowish white, absent on the body, except at the 
tip of the gaster and on the mandibles, clypeus and front. 
On these latter regions they are numerous, short, erect, 
stubby and obtuse. Scapes with short oblique hairs. Pubes- 
cence undeveloped, except on the tibiae where it is very 
short, dilute and appressed. 
Honey yellow; gaster and legs paler and more whitish 
yellow, the several gastric segments very faintly infuscated 
posteriorly; frontal carinae and mandibles red, the latter 
with black teeth and dental border ; impressions of the pos- 
terior orbits dark brown; claws and tarsal articulations 
reddish. 
Worker media. (Fig. 1 e and f) Length 3. 5-4.5 mm. 
Differing from the maxima mainly in the characters of 
the head, which is proportionately smaller and only 11/6 
to 1 1/5 times as long as broad; its posterior portion shorter 
and more rounded, its anterior portion more narrowed, with 
proportionally larger eyes, which are more convex, and 
reniform, i.e. with concave internal orbits and one half as 
long as the sides of the head. Posterior ocelli represented by 
minute pits in the larger, usually absent in the smaller 
specimens. Mandibles 7-8 toothed and more elongate and 
less convex than in the maxima, with less convex external 
borders and only the first, fourth and fifth tooth enlarged 
and more acute, the third, seventh and eighth very minute. 
Median portion of the clypeus longer, more convex pos- 
teriorly, its anterior portion more advanced and lobular, 
depressed. All the funicular joints longer than broad, except 
the penultimate. Thorax somewhat more slender than in the 
maxima, pronotum without longitudinal impression; meso- 
notum longer than broad, with more nearly parallel sides; 
its surface flattened and even slightly concave in profile. 
Petiole as in the maxima, but slightly more narrowed above. 
In the larger media there are distinct striae and short 
stubby hairs on the front, though the latter are less nu- 
merous; in the small media these hairs are absent and the 
striae are very indistinct or obsolete. Color like that of the 
