Five species (E. biguttatus, E. conterminus, E. oregon, E. quinquenotatus, and E. snowi). Three are polytypic.
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:
Postnotum expanded laterally at the spiracles.
Anal vein of posterior wing meeting the medial vein beynd the origin of the cubitus.
Possess a row of spines on the apical tarsal segments.
Possess an appressed, scale-like pubescence on the thorax, propodeum, and first tergite.
Some are marked with white on the abdomen.
In the north they are present from May through September, slightly longer in the south.
Adults capture orb weavers (Araneidae) (1)
to provision their nests. Adults also frequent flowers, especially males.
Females are fossorial and as stated above provision only with Araneid spiders. They have several generations per year.
The appressed, scale-like pubescence on the thorax, propodeum and abdomen is distinctive in nearctic pompilines. Structurally most similar to Poecilopompilus and Sericopompilus.
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. 1523-1571. 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.
Wasbauer, M.S., and L.S. Kimsey. 1985. California Spider Wasps of the Subfamily Pompilinae (Hymenoptera: Pompilidae). Bull. Calif. Insect Survey, Vol. 26