4 
Psyche 
[March 
1/3 its length, remainder of its surface only very feebly 
and superficially reticulate, definitely shining. 
(3) Petiole slender, with a long, slender peduncle and 
subglobose node; posterior spongiform collar vestigial; 
cariniform. 
(4) Ground pilosity of alitrunk reduced and mostly 
inconspicuous. Color light ferrugineous ; appendages, etc. 
and base of gaster lighter, more yellowish. 
Holotype (Mann Coll., USNM) one of a series of 15 
workers in the type series, taken at Rurrenabaque, Rio 
Beni, Bolivia (W. M. Mann leg.) 
Paratypes: (USNM, Coll. Borgmeier, MCZ) Remaining 
14 workers of type series, same data. TL 2.85-3.06 mm., 
HL 0.65-0.70 mm., ML 0.45-0.48 mm., WL 0.69-0.74 mm.. 
Cl 78-82, MI 69-70. Color varying from yellowish- to 
medium-ferrugineous. 
Strumigenys mixta new species 
Holotype ivorker: TL 2.32 mm., HL 0.54 mm., ML 0.31 
mm., WL 0.54 mm., Cl'83, Ml 57. 
Differs significantly from S. louisianae only in the fol- 
lowing details: 
(1) Inner mandibular border with an extra minute 
denticle slightly basad of the apical third of the ML. 
(2) Pilosity decidedly narrower and less conspicuous, 
especially on the posterior cephalic dorsum. Paired, out- 
standing hairs, one on each lateral occipital border, each 
humeral angle and each side of the mesonotum are all 
finely flagelliform, whereas in S. louisianae, the lateral oc- 
cipital and mesonotal hairs are stiff and spatulate towards 
their apices. 
(3) Metanotal groove completely or very nearly com- 
pletely obsolete; in profile from lateral view, the posterior 
alitruncal dorsum continuous in outline, not interrupted by 
the notch at the metanotal groove as in S. louisianae. 
Color light ferrugineous yellow. 
Holotype (USNM) one of 15 workers taken at Escuintla, 
Guatemala (W. M. Mann leg.). 
Paratypes : 14 workers from type nest series, same data 
