Psyche 
[September 
1 86 
dently a very old group, probably widespread during the early Ter- 
tiary in both hemispheres, and we may consider them as part of an 
early wave of the now dominant subfamily Myrmicinae that may 
have originated in an ectatommine stock near Gnamptogenys. We 
should expect the discovery from time to time of other fossil and 
living agroecomyrmecine relicts that will give us more details con- 
cerning the rise of the myrmicines. 
Tatuidris, genus nov. 
Worker: Size rather small, body exceedingly short and thickset. 
Head broad shield-shaped, narrowed in front and with strongly con- 
vex sides ; convex dorsally and concave beneath ; frontal carinae far 
apart, forming the lateral cephalic borders and the sharp upper mar- 
gins of deep, long antennal scrobes. Eyes small, convex. Antennae 
7-segmented, with a short, flattened-lamellate, apically broadened 
scape; funicular club indistinctly 2-segmented, the apical segment 
very large and thick. Clypeus broad, indistinctly bounded, trans- 
verse, with a sinuous, medially lamellate free margin. Mandibles 
heavy and robust, triangular, meeting along minutely crenulate but 
straight masticatory margins, each with two short, blunt teeth at 
apex and a massive brush of heavy setae along the inner (ventral) 
surface near the masticatory margin; each brush meshes with its 
opposite number at full closure (see Figure 3). Labrum broader 
than long, bilobed with a broad median excision. Maxillary palpi 
apparently 1 -segmented; labial palpi 2-segmented. 
Alitrunk remarkably short and broad, with continuously convex 
dorsum, forming an almost circular disc; humeri as seen in full dor- 
sal view rounded, but vertically carinate on sides. Propodeal declivity 
concave, unarmed but bounded on each side by a carina; inferior 
propodeal plates rounded. Petiolar and postpetiolar nodes subrec- 
tangular as seen from above, the postpetiole a little wider behind than 
in front, its sternum large and deep, and with an anterior rim 
Gaster truncate in front as seen from directly above. Sting very long 
and strong. 
Legs robust, femora and tibiae incrassate, tibiae obliquely termi- 
nated at apex, the extensor angle briefly produced and bearing a flat 
pencil of Stiff, curved yellow setae; these are much larger on the 
forelegs than on the others. On the forelegs, tarsal segments 2, 3, 
4 broadly triangular, with stout, darkened plantar setae; metatarsus 
with a dense brush of short yellowish setae occupying nearly the 
