What is "pompilus formosus"

Tarantula \Ta*ran"tu*la\, n.; pl. E. Tarantulas, L. Tarantul[ae]. [NL., fr. It. tarantola, fr. L. Tarentum, now Taranto, in the south of Italy.] (Zo["o]l.) Any one of several species of large spiders, popularly supposed to be very venomous, especially the European species ( Tarantula apuli[ae]). The tarantulas of Texas and adjacent countries are large species of Mygale. [Written also tarentula.]

Tarantula killer, a very large wasp ( Pompilus formosus), which captures the Texan tarantula ( Mygale Hentzii) and places it in its nest as food for its young, after paralyzing it by a sting.