334 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



Our species in this genus are 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 2 



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

 fuscous, the venation distinct. »^ 

 Metathorax coarsely rugose, with longitudinal raised lines, but without a 

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



P. CAUDATUS 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 rufous or honey yellow, the apex or petiole alone black. 



Metathorax rugose without a distinct central longitudinal carina. 



Rugosities longitudinal <? P. caudatus Say. 



Rugosities not longitudinal ^ P. kufigaster Prov. 



Metathorax rugose, with a distinct longitudinal carina. 

 All coxa3 black. 



Petiole not as long as thick. 



Four terminal abdominal segments black (? P. termixalis, sp. nov. 



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



All coxa? 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 ncrvures more or less distinct by fuscous streaks. 



Coxii' black or black basally. 

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



5 dentate, J P. californicus Holmgr. 



Metathorax coarsely rugose, but without a central carina; autenn;e simple, 



<? P. OBUquus, sp. nov. 



The discoidal nervures entirely wanting. 



Marginal cell always short 4 



Marginal cell large, as long as the stigma. 



Legs, including coxa>, pale yellow, the inner posterior tibial spur nearly as 

 long as the basal joint of the tarsi, ^ 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 carin*, inclosing 2 large smooth areas above; apex and sides 



rugose. 

 Coxtc black or dusky above. 

 Antennie brown, not extending to apex of thorax, basal two or three yellow. 



P. ABUUPTA Say^ 

 Coxie j>ale. 



Middle carina of metathorax ending at the superior edge of the rounded pos'^ 

 terior face. 



