 Janson also assembled a collection of world Elateridae ""It consists of 25,000 specimens of which at least 1000 are original types.Janson purchased the collection of this family made by M. Candeze, and which was the basis of his monograph.He also bought a second collection formed by Candeze, and he possessed according to a note found anmongst his papers the collections of Latreille, Dejean, Buquet, Reiche, Laferte, Gory, Parry, Deyrolle, Schaum (part), Bakewell (including Curtis), W.W. Saunders, Mniszech, E. Brown, A. Murray, H. Clark, and Atkinson.