Stelis costalis Cresson is an anthidiine cuckoo bee known from Texas and Mexico. Currently, it is placed in the subgenus Dolichostelis, a small group of seven species (; ). To date, its members have only been reported laying their eggs in the nests of various resin-using species of Megachile (Chelostomoides) (). Here, I report on the successful parasitism of a nest of the introduced resin-using bee, Megachile (Callomegachile) sculpturalis Smith by S. costalis.