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, 

 ua- in arrear of science. 1 



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

 Vaillant, 2 of ^o 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 

 cent res, 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 reeompo.se a general work. An excellent oppor- 



1 Wlien, 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 (Troschel's 

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

 fmirth 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. 



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

 ■ia. 



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 Vespidoz: — 



1. Description de quelques nouvelles Especes de Vespides du Musiede Lon- 



(Revne de Zoologie, VII. 1855.) 

 -■ - du Mexiqueet de V Amirique septentrional e. (Revue 



de Zoologie, IX, 1857.) 



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



4. Note sur les Polistes Americains. (Ann. Soc. Ent. de France, 1857.) 



5. Descripti n de quelques Vespides nouveaux. (Ibid.. 1857.) 



6. Bemerkungen Uber die gattnug Vespa. (Entomoi. Zeituue von Stettin. 



7. Sur divers V, spides Asiatiques et AJricains du Muse'e de Leyden. (Ibid.. 

 -•) 



