Females do not have any wings[1], instead they ride on adults female spiders until it lays eggs.[3] The male's wings are narrow and feature long marginal setae, with the longest marginal setae nearly as long as the maximum wing width. The hind wing is 8.5 times its maximum width, with the longest marginal setae measuring 1.6 times the maximum wing width.[2]
Female antennae is clavate. Males have antennae that are subclavate and have more segments.[3] The first and second abdominal tergites (T1 and T2) are characterized by numerous closely spaced ridges on T2. The genitalia feature well-developed digiti. Males appear closely related to those of Baeus japonicus, although B. japonicus exhibits a slightly narrower forewing and longer marginal setae.[2]
^ abMarshall, Stephen A. (2023). Hymenoptera: the natural history & diversity of wasps, bees & ants (First printing ed.). Buffalo, New York Richmond Hill, Ontario: Firefly Books. ISBN978-0-2281-0371-4.