Hi Guys,
there is always a lot of confusion on the publishing dates of the volume number 6 of the series Species des Hyménoptères d'Europe & d'Algerie, written by Robert du Buysson (in André) 1891-1896.
The following citation is the correct one:
Buysson, R. du (1891–1896) Les Chrysides. In André E.: Species des Hyménoptères d'Europe & d'Algerie. Tome Sixième. Vve Dubosclard, Paris, I–XII + 13–758 + 64 unnumbered pages + 32 pls. (1891) 1–88, (1892) 89–208, (1893) 209–272, (1894) 273–400, (1895) 401–624, (1896) 625–756 + 1*–22*, (1891–1896) 64 unnumbered pages + 32 pls. [Dating after Derksen & Scheiding 1963].
Here you can download the volume:
http://www.biodiversitylibrary.org/item/41020
Cheers
Paolo