334 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



Our species in this genus axe numerous, but may be readily deter- 

 mined by the aid of the following table: 



TABLE OF SPECIES. 



Head quadrate 6 



Head transverse. 

 Head and thorax black*. .:.. 3 



Head and thorax pale or rufons, the metathorax sometimes black, wings sub- 

 fuscous, the venation distinct. 

 Metathorax coarsely rugose, with longitudinal raised lines, but withoiit a 

 distinct central longitudinal carina; cauda as long as the abdomen. 



P. CAUDATU8 Say. 

 Metathorax coarsely rugose, not longitudinally striated, but with a distinct 

 central longitudinal carina ; cauda half the length of abdomen. 



P. PALLiDus Say. 



2. Abdomen black 3 



Abdomen rufons or honey yellow, the apex or petiole alone black. 



Metathorax rugose without a distinct central longitudinal carina. 



Rugosities longitudinal g P. caudatus Say. 



Rugosities not longitudinal i P. kufigaster Prov. 



Metathorax rugose, with a distinct longitudinal carina. . • 



All coxs« black. 

 Petiole not as long as thick. 



Four terminal abdominal segments black g P. terminalis, sp. noT. 



Three terminal abdominal segments black g P. Linkllii, sp. nov. 



All coxiE pale. 

 Petiole twice as long as thick. 



The sixth abdominal segment dusky P. melliventris Ashm. 



Petiole not as long as thick. 

 Four or five terminal abdominal segments black (P. terminalis. ) 



3. The discoidal nervures more or less distinct by fuscous streaks. 



Coxae black or black basally. 

 Metathorax coarsely rugose with a central carina; antennae with joints 1 to 



5 dentate. $ P. californicus Holmgr. 



Metathorax coarsely rugose, but without a central carina; antennje simple, 



(? P. OBLIQUUS, sp. nov. 



The discoidal nervures entirely wanting. ' 



Marginal cell always short 4 



Marginal cell large, as long as the stigma. 

 Lege, including coxae, pale yellow, the inner posterior tibial spur nearly as 

 long as the basal joint of the tarsi, g 9 P. flavipes Prov. 



4. Cauda short, not or scarcely one-third the length of abdomen 5 



Cauda as long as abdomen. > 



^ Legs, including coxa;, yellow, clypeus and mandibles light rufous. 



P. CLYPEATUS, sp. nov. 



5. Metanotum with 3 carinas, inclosing 2 large smooth areas above ; apex and sides 



rugose. 

 Coxae black or dusky above. 



• Antenna) brown, not extending to apex of thorax, basal two or three yellow. 



P. ABRDPTA Say. 

 Coxaet pale. 

 Middle carina of metathorax ending at the superior edge of the rounded pos- 

 terior face. * 



