THE TYPE SPECIES OF THE GENERA OF CHALCI- 

 DOIDEA OR CHALCID FLIES. 



By A. B. Gahan and Margaret M, Fagan. 

 Of the Bureau of Entomology, United States Department of Agriculture. 



INTRODUCTION. 



The modern tendency toAA'ard finer and finer "generic division, as 

 Avell as the practical limitation of human ability to describe com- 

 pletely and correctly, make it not only advisable, but in many in- 

 stances absolutely necessary, to have some ultimate basis for deciding 

 the characters of a genus. This can only be had by the fixing of a 

 definite species as type of each genus. 



The importance of genotype fixation is now very generally recog- 

 nized by zoologists, only a small minority still continuing to propose 

 new genera without indication of a type species. In the Hymenop- 

 terous superfamily Chalcidoidea the importance of type fixation was 

 recognized by several of the early writers, notably Latreille, West- 

 wood, Curtis, and Kirby. Various othei's occasionally indicated 

 genotypes, but few did so consistently, and not until the publication 

 by Ashmead of his work on the Classification of Chalcid Flies was 

 any serious attempt made to establish types for all the genera. Even 

 Ashmead confined his citations of types to genera which he considered 

 to be valid and ignored for the most part those which he considered 

 to be synonj^ms. Not a few of the fixations indicated by him are 

 erroneous by reason of earlier fixations or because they do not fully 

 conform to the established rules governing such fixations. 



Ashmead listed 901 generic names, including synonyms. In re- 

 cent years many new genera have been erected, the descriptions of 

 which are scattered through a large number of publications, some 

 with designated or automatically fixed genotypes, but a considerable 

 number still without definitely established type species. There is at 

 present available no publication making readily accessible the refer- 

 ences to descriptions of many of these genera, and it is also fre- 

 quently a matter of considerable difficulty to ascertain the genotype 

 species of a given genus. 



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