Insecta Britannica Diptera is a seminal work of entomology by Francis Walker.
The work spans three volumes; a fourth volume was never published.
Parts of the work were credited by Walker to Alexander Henry Haliday, including the characters and synoptic tables of the Empididae, Syrphidae, and Dolichopodidae[1] and addenda and corrigenda intended for volume 4.
[2] The precise dates of early entomological publications are frequently hard to establish.
A digitized version of the work can be found at the Internet Archive: This article about a book on zoology or animals is a stub.