1966] 
Gotwald and Brown — Simopelta 
269 
Type nest series taken a short distance (about 1/2 km) beyond 
(NW of) the bridge over the Rio Toro Amarillo, near Guapiles, 
Limon Province, Costa Rica (N. Scott and W. L. Brown, Jr. leg.). 
Holotype worker deposited in Museum of Comparative Zoology, 
Harvard University, together with queen from type nest. 
Paratype series: 42 workers from type nest series taken “random- 
ly” from a larger series in alcohol; 10 measured, including the ap- 
parent largest and smallest specimens: TL 3. 6-3. 9, HL 0.79-0.81, 
HW 0.57-0.60, ML 0.21-0.24, WL 1.31-1.40 mm. Cl 72-74. 
Non-metric variation: Color varies from predominantly deep cas- 
taneous to piceous, with the head nearly black. Sculpture on sides 
of alitrunk and petiole varies somewhat in distinctness and direction. 
Upon dissection, 4 live workers each proved to have 4 Malpighian 
tubules. 
Paratypes deposited in Museum of Comparative Zoology, Harvard 
University; Cornell University Collection; Departamento de Zoo- 
logia, Sao Paulo ; California Academy of Sciences, and elsewhere. 
Queen (a single dichthadiiform female from type nest, gaster 
contracted) : TL 3.6, HL (from anterior clypeal border) 0.68, HW 
(without eyes) 0.67, WL 1.18, greatest diameter of eye 0.11, scape 
L 0.46 mm. Cl 99. 
Shape of head and body shown in Figs. 2, 11-13. Outstanding 
differences from the worker may be seen in the shape of head, an- 
tennae and mandibles, thoracic sclerites, deeply bilobate petiole, and 
broad gaster with median sulcus on the first tergum. Eyes a bit more 
elongate and showing more traces of facetting, set obliquely on sides 
of head. Funicular antennomeres broader than long, except first 
and last. A single small median ocellus, in front of which is a broad, 
transverse shallow sulcus. Sting well developed and extrusible. 
Femora slightly flattened, weakly incrassate, the broad faces feebly 
sulcate. First gastric tergum with a broad, shallow, longitudinal 
median sulcus, in the middle of which is an indistinct pore. Lower 
edge of metapleural gland bulla cultrate, conspicuously ivory in 
color; meatal guard hairs 5-6 in number, long and fine. 
Sculpture mainly smooth to nearly smooth, shining; head and an- 
terior dorsum of alitrunk shallowly roughened and with indistinct 
punctures; finer piligerous punctures scattered over propodeum, 
petiole and gaster. Appendages finely, densely and shallowly punc- 
tulate, weakly shining. Entire body, including mandibles and ap- 
pendages, but excluding large parts of coxae and sides of alitrunk, 
with abundant fine, yellowish-white, decumbent to suberect pilosity 
