VI PREFACE. 



during the three years, while the manuscript had lingered in the 

 hands of the printer, there had appeared a memoir, by Dr. Mobius, 

 on Wasps' Nests, so that my work, at the time of its publication, 

 was in arrear of science. 1 



To these contingencies I must add the death of the artist M. 

 Vaillant, 3 of so interesting memory, during the publication of the 

 first volume. The succeeding draughtsmen, by whom I replaced 

 him, were far from equalling him, and have often produced infe- 

 rior, sometimes even bad drawings. 3 



It will be easily understood that all these vicissitudes have not 

 a little contributed to render the work defective. From the very 

 first, I have felt the necessity of recasting it. But as I could not 

 undertake fresh journeys to visit the collections in distant 

 centres, Paris, London, etc., I have adopted another method, 

 which consists in correcting and completing my studies on the 

 Family of the Vespidse by means of successive memoirs, result- 

 ing from the study of collections, which are kindly communi- 

 cated to me. 4 All these works, together, will perhaps enable 

 me one day to recompose a general work. An excellent oppor- 



1 When, at length, the work was completed by the tardy appearance 

 of the general part of the 2d volume, Mr. Gerstacker spoke of this general 

 part in his annual report on the progress of Entomology (TroscheFs 

 Archives), calling it. I know not for what reason, the commencement of a 

 fourth volume. He reproached it disparagingly for not noticing recent 

 works. True it is, he could not guess that it was an old laggard which 

 had been some years in press. 



2 Mr. Vaillant was the artist attached to the scientific exploration of 

 Algeria. 



3 The drawings of the PI. XVI, of Tome I, are in particular very bad. 



4 I have thus composed the following memoirs, forming, as it were, a 

 supplement to my Studies on the Vespidce: — 



1. Description de quelques nouvelles Espechs de Vespides du Musee de Lon- 

 dres. (Revue de Zoologie, VII, 1855.) 



2. Nouveaux Vespides du Mexique et de VAmtrique septentrional e. (Revue 

 de Zoologie, IX, 1857.) 



3. Note sur la Famille des Vespides. (Ibid., X, 1858.) 



4. Note sur les Polistes Americains. (Ann. Soc. Ent. de France, 1S57.) 



5. Description de quelques Vespides nouveaux. (Ibid., 1857.) 



6. Bemerkungen iiber die gattnug Vespa. (Entomol. Zeitung von Stettin, 

 1857.) 



7. Sur divers Vespides Asiatiques et Ajricains du Musee de Leyden. (Ibid., 

 1862.) 



