[3] Nearly all species are solitary (with the exception of some group-nesting Ageniellini[4]), and most capture and paralyze prey, though members of the subfamily Ceropalinae are kleptoparasites of other pompilids, or ectoparasitoids of living spiders.

[5] In South America, species may be referred to colloquially as marabunta or marimbondo, though these names can be generally applied to any very large stinging wasps.

The metathorax is solidly fused to the pronotum and mesothorax; moreover, the prothorax is best developed in Pompilidae and Scoliidae because wasps in these families use their forelegs to dig.

The pompilid body is typically dark (black or blue, sometimes with metallic reflections), but many brightly colored species exist.

[10] Other fossil species are known from Dominican and Baltic ambers, the Florissant Formation and various other localities in Germany, France and Spain.

Typically, a single egg is laid on the abdomen of the spider, and the nest or burrow is closed so the larva can develop without disruption by other parasites or scavengers.

[15] The female wasp may then engage in spreading soil or other changes to the area, leaving the nest site inconspicuous.

As the larva feeds on its host, it saves the vital organs, such as the heart and central nervous system, for last.

By waiting until the final larval instar, it ensures the spider will not decompose before the larva has fully developed.

[20] Pepsis thisbe of the southwestern United States exhibits a direct correlation between adult wasp body length and the weight of its host spider, Aphonopelma echina.

Specific chemosensory cues attract the wasp to its prey, Aphonopelma echina, despite other host spiders of the same size and frequency being present.

In studies on Pepsis grossa (formerly P. formosa),[22] a pompilid of the southwestern United States, the wasps were found to have behavioral plasticity.

Concerning mating behavior, males acquire perch territories to scan for incoming receptive females.

The Pompilidae produce a venom, delivered when they sting, containing a variety of powerful neurotoxins named pompilidotoxin (PMTX).