Image Credit: Entomart
Solitary Wasps (Sphecidae+) – predators – I believe all solitary wasps (previously included in the superfamily Sphecoidea) are flower-visitors for both nectar and mating. Most solitary wasps attack herbivorous insects (mostly beetles, flies and caterpillars), paralyze them with a sting, and transport them to their nests to feed them to their young. Many solitary wasp species can be confused with the true bees, especially Hylaeus, the shiny black panurgines, and various males of melanic taxa. One technical distinction is the width of the basitarsus (1st toe segment) on the hind leg: in wasps the basitarsus is generally less than 2x the width of the other toe segments, but in bees (especially the females) the width is >2x the succeeding segments.
Both solitary wasps and bees are distinguished from hornets and spider-wasps by the reduction in size of the pronotum to two tiny circles on either side of the neck. On the wasp at the right, the tip of the pronotum is one of the 2 orange circles at the base of the wings (the other is the tegula, which is a shield protecting the base of the wing); the total pronotum extends to the other side encompassing the 2 orange neck spots. (see the picture above for the pronotum of a hornet)