Pepsis mexicana

On this page and the iNaturalist page showing images associated with research-grade observations of Pepsis mexicana, it's seen that the wasp is black, usually with a metallic-blue sheen; wing apexes exhibit white edges if they haven't worn away.^[3] Wing color and the wings' narrow, white apex borders distinguish Pepsis mexicana from other tarantula-hawk species.^[4] Male Pepsis mexicana wasps are about 20mm long (~+3⁄4 inch), while females are about 3mm longer (~+1⁄8 inch).^[5] While Pepsis wasps are among the world's largest wasps, relative to other Pepsis species, the Mexican Tarantula-hawk Wasp is regarded as a small to medium species.^[4]

Pepsis mexicana occurs from the Southwestern United States (the Mojave Desert of southern California, the Sonoran Desert of southern Arizona and the Chihuahuan Desert of western Texas) south through Mexico and Central America into Costa Rica. In the Mexican state of Chiapas it ascends to 2500m (8200 feet).^[4]

As with all members of the genus Pepsis, females of Pepsis mexicana capture and paralyze large theraphosid spiders (tarantulas) as a source of food for their carnivorous larvae. After stinging and paralyzing the tarantula, the female wasp drags it into the tarantula's former burrow or within a previously excavated nest. A single egg is deposited on the abdomen of the victim, then loose soil is compressed over the spider and egg. Both male and female Pepsis wasps feed on nectar of various flowering plant species.^[5]

With regard to stings of humans, clinically it's established that though "... the instantaneous pain of a tarantula hawk sting is the greatest recorded for any stinging insect, the venom itself lacks meaningful vertebrate toxicity."^[6] It hurts a lot, but doesn't damage. Male tarantula hawk wasps don't sting, and females rarely sting humans without being provoked.^[7]