456 PROCEEDINGS OF THE ACADEMY OP [1898. 



sometimes wanting at apex of petiole, pale yellow ; mandibles red- 

 dish. 



Clypeus with shallow punctures, broader than long, obtusely 

 angular anteriorly ; ocelli forming a low triangle in consequence of 

 the hind pair being nearly twice as far apart as they are from the 

 anterior one, the distance between the hind pair about equal to that 

 between them and eyes ; the latter almost reaching base of mandi- 

 bles ; flagellum subclavate, the first joint about as long as the follow- 

 ing two united ; pronotum short, margined ; dorsulum barely longer 

 than broad, middle segment short, rather concave, with a narrow 

 raised line down middle on each side of which there is a furrow ; 

 petiole shorter than hind femur, elongate and tolerably stout, gradu- 

 ally enlarged from near base, much more slender than in P. socialise 

 remainder of abdomen subovate ; legs robust; wings subhyaline 

 throughout; nervures and stigma dark; third submarginal cell 

 higher than long, the outer nervure angulate before its junction with 

 the cubital vein. Length 11-12 mm. 



$ . — Colored like 9 °r $, but having the usual sexual differences • 

 smaller clypeus, narrower front, antenna? longer and acuminate at 

 tip ; otherwise agreeing with the preceding description. 



Chapada, October and November. Ten females (workers ?), one 

 male. Allied to P. socialis, but the more slender petiole excludes it 

 from Saussure's II, Division Iota. These divisions are not natural, 

 however. 



Polybia marginata n. sp. 



9 or $ — Thorax, petiole and legs reddish brown, the first men- 

 tioned with thin golden pile; head, and body of abdomen black; 

 sides of thorax and petiole apically dusky ; line on inner orbits be- 

 low emargination, on posterior orbits above, line on pronotum 

 anteriorly and posteriorly, fore margin of postscutellum, two lines on 

 middle segment, spot on four hind coxa?, and at tip of all femora, 

 pale yellow. 



Head subquadrate, not very transverse; ocelli forming an equi- 

 lateral triangle; first joint of flagellum nearly as long as the three 

 following united ; pronotum sharply margined anteriorly ; dorsulum 

 about one-fifth longer than broad ; middle segment concave medially ; 

 petiole elongate, slender, broadened from beyond middle, altogether 

 more slender than P. sericea, in length greater, if anything, than 

 hind femur ; wings dark, paler apically, black in costal cell ; breadth 



