1898.] NATURAL SCIENCES OF PHILADELPHIA. 447 



band at apex of first segment to forms with the abdomen almost 

 entirely yellow. 



Polistes carnifex Fabr. 



Chapada, October, December, January ; Rio de Janeiro, Novem- 

 ber ; Corumbd, April ; Santarem. Nine specimens. 



Polistes ruficornis Sauss. 



Chapada, February to April, June. About 35 specimens. The 

 amount of red and black on thorax is variable. The prothorax and 

 scutellum may be either color. 



Polistes cinerascens Sauss. 



Chapada, February, March, June ; Rio de Janeiro, November. 

 Ten specimens. 



Polistes pacificus Fabr. 



Mararu, April ; Santarem. Six specimens. 

 Polistes acteon Hal. 



One specimen. Rio de Janeiro, November. 

 Polistes subsericeus Sauss. 



Sixteen specimens. Chapada, March and December. 

 Polistes thoracicus n. sp. 



Brick red; sides of middle segment, metapleura and mesopleuroe 

 sometimes, and four hind coxae, more or less, black ; wings yellow- 

 ish. The following parts are obscurely yellow, or of a paler tint 

 than most of body : head in front, cheeks, hind margin of pronotum, 

 teguhe, scutellum, postscutellum, apical margin of segment 1 and 2, 

 and 3-6 entirely yellow. 



9 . — Clypeus longer than broad, obtusely angular anteriorly ; 

 space between hind ocelli about equal to half that between them and 

 eyes, the latter separated from base of mandibles by a distance equal 

 to the fourth, fifth and half of sixth joints of antenna?; pronotum 

 strongly margined ; dorsulum nearly one-quarter longer than broad ; 

 middle segment with indistinct transverse striations. Length 16- 

 17 mm. 



$ . — Antennae longer ; striation of middle segment coarser. 



Chapada, February to April. Related to P. carnifex, but is much 

 smaller, with black sides of thorax, comparatively longer clypeus. 

 It is larger than P. ruficornis, of which it might be taken for a 

 variety, and the clypeus is much longer. The coloration is quite 

 constant in the six specimens before me. 



