PREFACE. 



In working since 1902 on the classification of the Ichneumonoidea, 

 a complex with some 25,000 species distributed among over 2,000 

 genera, it soon became evident to the writer that in order to do the 

 most satisfactory work one of the first steps was to being up to date 

 and keep up to date Dalla Torre's admirable catalogue. So far as 

 the North American forms were concerned, this had been done prior 

 to 1909, when the writer joined the Bureau of Entomology, United 

 State Department of Agriculture. During the following four years, 

 while in the Bureau of Entomology, the wiiter extended the work of 

 cataloguing so as to include the whole world. This led up to the 

 consideration of all known genera, and finally to the adjustment of 

 their names by means of ascertaining the legal type of each genus, 

 where the type had been already selected, and the designation of a 

 type in aU other cases. 



The necessity for such a procedure must be patent to all true 

 friends of science, when it is remembered that one of the cliief ends of 

 scientific nomenclature is stability and that this end can be best 

 approximated, where generic names are at issue, by arguing the case 

 of each name from the standpoint of the definite premise — -the type 

 of the genus — just as in the case of the species the type of each 

 species is the final court of appeals. 



The following l)ulletin is the result of an attemj>t to put each 

 Ichneumonoid genus upon a definite basis. 



Henry L. Vierkck. 



