IV PREFACE. 



With the ho|)e that .such may prove to be the case, the following 

 tables have l)een compiled from the writings of Wesmael, Holmgren, 

 Westwood, Thomson, Taschenberg, Norton, Marshall, Andre, Mayr, 

 Saunders, Howard, Cau)eron, Ashmead and others. Little or nothing 

 original in the arrangement is claimed by the compiler. The char- 

 acter' given in many cases, especially in the Tchneumonidse, are very 

 unsatisfactory, otlen difficult to describe intelligibly, and yet they 

 are about the best that can be offered with our present incomplete 

 knowledge. Doubtless, after more careful study has been made, new 

 and more reliable characters will be discovered, that will make the 

 divisions more easy, simple and correct. 



As a rule, only such genera as have been found to occur within 

 our faunal limits are characterized in the synoptic tables given herein, 

 but in some families, e. g. Ichneumon idie, Braconidae, Chalcididie 

 and Proctotrupidoe (our material of which has been so little studied), 

 some of the European genera, not yet recognizetl with us, but prob- 

 sd)ly will be, are added, and are indicated by an asterisk preceding 

 the name. 



As an aid to the student, the synopsis is followed by an approxi- 

 mately com{)lete catalogue of the species that have been described sis 

 inhabiting our fauna, closing with a list of works and papers having 

 reference to our Hymenoptera. 



In conclusion, the compiler desires to express his thanks to the 

 Rev. T. A. Marshall and Messrs. L. O. Howard, W. H. Ashmead 

 and George B. Cresson, who have most kindly aided in the prepara- 

 ti<m of this paper ; nnd especially does he feel grateful for the kind- 

 ness and friendship of Dr. George H. Horn, who has most cheerfully 

 and willingly given largely of his valuable time and much needed 

 information and advice. 



