David Clements prepared a set of keys to the 'picture-wing' fly families for the Dipterists Forum workshop at Preston Montford in February 2020. These keys are now available to download from the DF membership area (under the Resources menu). The keys cover a set of families of acalypterate flies, all of which have species with prominent wing markings: Tephritidae, Ulidiidae, Platystomatidae, Pallopteridae and Opomyzidae.
Many thanks to David for making these keys available. If you would like to access the DF membership area but are not a member, please do join us!