Mémoires pour servir à l’histoire des insectes. 6 vols.

Réaumur’s greatest work describes the appearance, habits and locality of all the known insects except the beetles, and includes 267 plates. Posthumously published: Tome VII: Histoire des fourmis, (Paris: Paul Lechevalier éditeur, 1928), and Histoire des scarabées (Paris: Paul Le Chevalier éditeur,1955) with 21 plates.

The first portion of Reaumur's encyclopedic work that was translated into English appears to have been his studies of bees. This was translated by Gilles Auguste Bazin and as published as The natural history of bees:  Containing an account of their production, their oeconomy, the manner of their making wax and honey, and the best methods for the improvement and preservation of them (London: J and P. Knapton, 1744). Digital facsimile of the 1744 edition from the Biodiversity Heritage Library at this link. Digital editions of all six volumes of the original edition of the Mémoires are available from the Internet Archive at these links.