Yikes! There are some pretty interesting and intimidating insects. The Ensign wasp is one of them! You’ll typically come across this insect outdoors, however this wandered indoors (perhaps to look for cockroaches?) Ensign wasps have small compressed abdomens that move up and down (like a sign, hence their common name). There are 11 different species of ensign wasps, however the most common is Evania appendigaster.
Adult are usually solid black in color and about 1/4 to 3/4 inch long. They can often be confused for a cricket or a spider due to their color and long legs. These are solitary wasps that can be beneficial in the garden (and for your home). Ensign wasps are considered parasitic wasps, as they lay their eggs inside the egg cases of cockroaches. While they usually lay their eggs outdoors under leaf litter, where cockroaches often nest, they can also make their way indoors if roaches are present in a home. The female lays a single egg in the cockroach egg case. When the larva hatches it feeds on the egg for its first stage of development, then moves on to eat the other eggs as it grows. As adults, ensign wasps will feed on nectar and honeydew and only live about 2-3 weeks. These wasps don’t bite or sting humans, so there’s no need to fret if one wonders indoors. Best to catch and release them back outside if you can!