This is a key by Fritz Geller-Grimm & M. J. Smart . It covers the central European counterparts to our Choerades. This key is posted on Fritz Geller-Grimm's homepage on asilids.

Robber Flies (Diptera: Asilidae) New to Canada, British Columbia, Yukon and the Northwest Territories: With Notes on Distribution and Habitat

This is a research paper by Robert A. Cannings, Royal British Columbia Museum, Victoria, B.C. It contains a variety of records for Laphria s. str., Choerades, and both new genera, all under the name Laphria (i.e., s. lat.).