56 
William Morton Wheeler 
shorter and somewhat broader than the petiole, convex above and 
constricted behind. Gaster about as large as the head, with very 
large first segment into which the remaining segments are withdrawn. 
Legs long, femora somewhat incrassated; middle and hind tibise 
without spurs. 
Electromyrmex klebst Wheeler. 
Electromyrmex Klebsi Weehler, Ants, Their Structure, etc. 1910, p. 164, Fig. 94, £. 
Worker (Fig. 21). Length about 5,5 mm. 
Mandibles, clypeus, pronotum, gaster and legs apparently smooth 
and shining; head with sharp, longitudinal rugse running its entire 
length; mesopleurse and epinotum 
regularly and transversely, petiole 
and postpetiole longitudinally rugose. 
Hairs short, sparse and erect 
on the body and mandibles, appa- 
rently absent on the scapes and 
gaster. 
Color black throughout, more 
or less of the surface with a sil- 
Fig. 21. Electromyrmex klebsi Wheeler. ver y 
Worker. K 2658. Described from a single spe- 
cimen (K. 2658) in the Klebs Coli. 
This singulär ant is so unlike any of the recent species known 
to me in the structure of its mandibles, thorax and petiole that it 
evidently deserves to rank as the type of a new genus. The specimen 
has the tip of the gaster involved in a white cloud and much of the 
sculpture on one side is obscured by bubbles and air films, but the 
main characters are sufficiently distinct. The large, anteriorly placed 
eyes and the slender body and appendages indicate that the insect 
was an exquisitely arboreal form like the recent species of Sima and 
Pseudomyrma. 
Genus Ayroecomyrmex , gen. nov. 
Worker. Body short and thickset. Head subrectangular, 
scarcely longer than broad, slightly broader behind than in front, 
with rounded sides and posterior angles and small, very convex eyes 
placed very near the posterior angles, and deep antennal scrobes 
running from the antennal fovese to the inner border of the eyes. 
Ocelli absent. Mandibles, short, convex, with 5 subequal teeth. Clypeus 
