At least two of these wasps, perhaps one male and one female, have been visiting a Mason bee shelter behind my house on a regular basis. The wasps appear to be black to the naked eye, but photos taken with a flash indicate that portions of the body are translucent and that there is an orange abdominal segment just below the waist. These wasps visit the shelter, often entering the tubes. Some of the tubes appear to be sealed. I have not observed them taking anything into the tubes. After entering a tube, the wasps do not exit immediately.