392 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



Abdomen poiiitt'd-ovate, the petiole ratliei- long, fluted; the second 

 segment occupies the greater part of its surface, with sulci at base; 

 the apical joint pointed, stylus-like. 



Legs rather long, ])ilose. tlie femora clavate, the i)osterior tarsi a little 

 longer than the tibia', or fully as long, the basal joint one-third longer 

 than the second. 



The genus is sufficiently distinct from the other getiera with 13- 

 jointed antenme by the length of the submarginal vein, the absence of 

 a basal nervure, the more pointed abdomen, the second segment with 

 sulci at base, and by the antennal characters of the male. 



I am not aware that anything has been published respecting the 

 habits of the genus, but if my memory serves me rightly 1 saw speci- 

 mens of P. tkJijx'S Westw. in the ]>crlin Museum, reared from Eristalis 

 tcnax^ along Avith Diaprid conica. 



Our sjiecies seem to be quite distinct from the described European 

 species, and may be recognized by the aid of the following table: 



TABLE OF HPEf'IES. 



femai.es. 



Whigs snldiyaline or tinged with fuscous 2 



Wings hyaliuo. 

 Antenna; honey-yellow or brownish-yellow, clavate-moniliform, 



Flagellum twice as long as the scajie, the 5 or G terminal joints fuscous or 

 black, the last enlarged, fusiform, more than thrice as large as 

 as the penultimate; legs brownish-yellow; abdomen entirely 



black P. PARVULCS, sp. nov. 



Flagellum elongated, the last joint only black, globose-ovate; legs honey- 

 yellow. 

 Mesonotal furrows complete; abdomen pale at base.. .P. tkrminatus Say. 

 Mesonotal furrows wanting; abdomen not pale at base.. P. clavipes Ashm. 

 Antenna- fuscous or black. 

 Flagellum 2i times as long as the scape, the last joint fusiform, about thrice 

 as large asthepennltimate; legs pale reddish, all coxa' black, 



the femora dusky P. I'TAHENSIS, hji. nov. 



2. Antenna^ and legs reddish-yellow. 

 Last I'our joints of antenna' black. 



Scutcllum Avith two fovcic at base; K{;a])ula' with a grooved line. 



r. sriNosus, sp. nov. 

 Scutcllum unifoveafe, the fovea creuulatc; scajiubc without a groove. 



P. PALLIDITES, sp. UOV. 

 MALES. 



Wings fusco-hyaline. 



Legs, iuchuliug coxa-, pale brownish-yellow; antenna' pale ferruginous. 

 Pedicel and the first fnniclar joints of an e(|ual leugth, the joints beyond 

 sliglitly more than 4 times as long as thick. 



P. PALLIDIPES, sp. nov. 

 Pedicel a litth; shorter but stouter than the first funiclar joint, the joints be- 

 yond very long, several times longer than thick. 



P. spiNosrs, sp. nov. 



Wings dark, fuscous. 



Legs ferruginous, all coxiip and the swollen portion of femora black, the tibia; 



toward apex more or less fuscous; autenn* black, the pedicel 



shorter than the first funiclar joint. .P. oreconensis, sp. uov. 



