340 
Psyche 
[December 
Petiolar node pyriform or subclavate, with feebly suggested pedun¬ 
cle, about 0.47 mm wide across the widest part (near posterior end) in 
holotype, and about 0.66 mm long. Ventral keel forming an obtuse 
tooth just behind midlength. 
Postpetiole with broadly rounded sides, diverging caudad to the 
greatest width, a little before the posterior margin (W 0.89 mm in 
holotype), which is rather sharply constricted. Median posterodorsal 
surface of postpetiole weakly set off as a high, rounded boss; antero- 
ventral shelf or lip well developed, trailing a short, septate carina 
caudad. 
The remainder of the abdomen forms the most extraordinary 
structure of this body region known among the ants (figure 1). The 
second gastric (fourth true abdominal) tergum is grossly hypertro¬ 
phied posteriad beyond the anteroventral opening, from which issues 
the true abdominal apex, with the exserted apical segments extending 
ventro-cephalad. The hypertrophied posterior extension of the 
second gastric tergum is permanently curled anteroventrad to form a 
short, bluntly rounded, false gastric apex, so that the real sternum of 
this segment is externally represented only by a small anteroventral 
piece, triangular in side view. The incurled ventral surface of the 
tergal extension is furnished with a series of coarse, sharp rugae that 
tend to extend vertically or obliquely part way up the lateral surfaces, 
and run partly transversely across the concavity in the holotype (in 
the paratype worker, the posterior rugae tend to run lengthwise, 
following the curve of the curl). From above, the hypertrophied 
tergum is cylindrical, 1.3 mm long, with almost straight (very feebly 
concave), parallel sides and a broadly rounded posterior outline, and 
is almost exactly (0.87 mm) as wide as the postpetiole. (In the para¬ 
type, maximum postpetiole W 0.92 mm, maximum second tergal W 
0.90 mm.) 
In both specimens the gastric apex is extended as 3 stout visible 
segments and the strong, exserted sting; undoubtedly these are all 
retractile to some degree. 
Legs rather long and slender, though both femora and tibiae are 
gradually incrassated from base toward apex; hind leg: femur L 1.53, 
tibia L 1.26, metatarsus L 1.0 mm. Tibial spurs one on each leg (small 
on mid tibia), pectinate, but only feebly so on mid tibia. Claws on all 
legs slender, simple. 
