240 PROCEEDINGS OF THE NATIONAL MUSEUM vol.88 



The measurements of the width of the malar space, the interocular 

 space, and the height of the compound eyes have been uniformly 

 made from the anterior aspect. It is obviously necessary to measure 

 all specimens from the same angle, as none of the areas to be measured 

 is flat; the width of the compound eye varies widely if specimens 

 are not all measured from exactly the same angle. The lengths of 

 the various segments of the antennae have been measured from the 

 dorsal aspect; measurements made from any other angle will not 

 agree with those given here. The length and width of the petiole 

 have, likewise, been measured from the dorsal aspect. 



ACKNOWLEDGMENTS 



I wish to express my indebtedness to the directors of the Bache 

 Fund of the National Academy of Sciences for a grant that made 

 possible the study of the materials in the United States National 

 Museum and the Academy of Natural Sciences of Philadelphia. 

 A. B. Gahan, of the U. S. Bureau of Entomology and Plant Quaran- 

 tine, very kindly gave much helpful advice and generously permitted 

 me to use the notes he made in several European museums on a 

 number of important types of Chalcididae. Dr. H. H. Ross, of the 

 Illinois State Natural History Survey, aided in the solution of many 

 difficulties encomitered during the preparation of this study. The 

 authorities of the Academy of Natural Sciences of Philadelphia 

 granted permission to study and dissect, where necessary, the im- 

 portant Cresson types. Dr. Ch. Ferriere, of the British Museum, 

 kindly furnished information on types, made comparisons with sev- 

 eral of Walker's and Kirby's types, and lent for study a cotype of 

 Sniicra ruflpes Kirby. Dr. Olaw Schroeder, of the Kiel Museum, 

 made comparisons with the types of the two Fabrician species from 

 this area. Dr. Richard Dow, of the Boston Society of Natural His- 

 tory, compared specimens with the type of Chalcis hracata Sanborn. 

 Dr. G. N. Wolcott, of the Insular Agricultural Experiment Station 

 of Puerto Rico, assisted by lending the types of his species Spilo- 

 chalcis syrphidis and S. homledrae for study. Dr. J. C. Bradley, 

 of Cornell University, lent a number of paratypes of Cameron's 

 species described from the Baker collection. Dr. Lucien Berland, of 

 the Museum National d'Histoire Naturelle, Paris, generously fur- 

 nished information on types located in that institution, made com- 

 parisons with several types, and lent for study cotypes of Smicra 

 conjungens Walker and Conura scutellaris Sichel. 



This revision is based principally on the collection of the United 

 States National Museum. The following individuals and institutions 

 have lent, in addition, over 2,000 specimens : 



