1944] 
A New Fungus Growing Ant from Mexico 
5 
A NEW FUNGUS GROWING ANT FROM MEXICO 
By William F. Buren 
Alexandria, Louisiana 
Trachymyrmex smithi, n. sp. 
Worker. 
Similar to T. septentrionalis obscurior but black in color and 
with several structural differences. 
Length about 3.5 to 4.0 mm. 
Head, excluding mandibles, a little broader than long, wider 
behind than in front, with the hind border excised in an obtuse 
angle, and the sides feebly convex. Head broadest midway be- 
tween the eyes and posterior corners. Clypeus broadly notched 
in the middle. Frontal carinae more mesally placed than in many 
species of Trachymyrmex , produced laterally into sub triangular 
lobes in front, becoming faint behind and fading out before 
reaching the hind border of the head. Scapes surpassing posterior 
corners of head by about one fourth of their length. All funicular 
joints longer than broad. Antennal scrobes indistinct behind. 
Genal carinae curving obliquely mesad past the level of the eyes. 
No postocular carinae. Eyes hemispherical. A single short blunt 
spine behind each posterior corner of the head. 
Thorax rather robust. Mesoepinotal impression moderately 
deep. Inferior pronotal spines small and lappet-shaped. Median 
superior pronotal spines separate and rather blunt. Lateral 
pronotal spines blunter than in obscurior , projecting laterally and 
curving slightly ventrad toward the tip. Three pairs of spines on 
the mesonotum. The first pair not as long as the lateral pronotal 
pair but blunter and more robust, broader at the base than high. 
The posterior two pairs of mesonotal spines much smaller and 
somewhat sharper. Epinotal spines slender and sharp. Rows of 
tubercles run forward on the epinotum from the epinotal spines 
to form longitudinal carinae, and other rows of tubercles form 
rather feeble oblique carinae on the pleurae of the epinotum and 
mesonotum. 
Petiole and postpetiole much as in obscurior but the petiole is 
longer, its anterior dorsal face more sloping. Postpetiole notched 
