Three species; two are polytypic in North America, the other is polytypic but only one subspecies occurs in North America.
This genus belongs to the subfamily Pompilinae, tribe Pompilini and is identified by the following characters:
Spines at apex of hind tibia of unequal length and spacing.
Hind tibia always smooth in nearctic species.
Dorsal side of hind femur with at least a few spine pits.
Pocket in the basioposterior corner of the third discal cell.
Labrum at least partially concealed.
Females of this genus possess a tarsal comb.
This genus is identified by the following characters:
Anal vein of anterior wing meeting the medial vein beyond the origin of the cubitus.
Postnotum expanded laterally at the spiracles.
Apical tarsal segments with a row of spines beneath.
Eyes strongly convergent above, lacking scale-like pubescence.
Most subspecies are marked with black, yellow, and ferruginous in various patterns. These are some of the most ornate spider wasps in North America.
Transcontinental as a genus. P. algidus and P. interruptus are widespread. P. flavopictus is restricted to southern Texas.
Meadows, woodland edges and openings with sandy soil.
Typically found in late summer to early autumn in northern states, in flight for a longer period of time in the southern states.
Adults are frequently feed from flowers. This genus provisions with Araneid and Nephilid spiders.
This genus is fossorial. There is one generation per year in the north.
Although they share structural similarity and relationship to both Episyron and Sericopompilus they are easily separated from these two genera.
Evans, H.E. 1950. A taxonomic study of the nearctic spider wasps belonging to the tribe pompilini, Part I. Trans. Amer. Entomol. Soc., 75: 133-270.
Krombein, K.V. 1979. Pompilidae, pp. 1550-1551. In Krombein, K.V., P.D. Hurd, Jr., D.R. Smith, and B.D. Burks, eds. Catalog of Hymenoptera in America North of Mexico. Vol. 2 Apocrita (Aculeata). Smithsonian Inst. Press, Washington, D.C. (species, distribution, references).