1887 89 p., 3 plates, paperbound (original printed covers).Probably a fore-runner of Frey-Gessner's "Fauna insectorum Helvetiae. Hymenoptera: Apidae". From the library of Dr. H. Franz, Vienna, with his small stamp in the front wrapper top margin and some corrections in the text. Cover split at fold, otherwise a good copy. Rare, not in Horn-Schenkling.