INTRODUCTION. 



This Volume includes an enumeration of the species of fifteen Families of Hymenoptera : 

 four of the section Sessiliventria — Tenth redinidae, Cephidae, Siricidae, and Oryssidae ; and 

 eleven of Petioliventria — Cynipidae, Figitidae, Chalcididae, Ichneumonidae, Braconidae, 

 Stephanida3, Evaniidae, Trigonalidae, Pelecinidae, Proctotrupidae, and Chrysididae. It 

 was commenced by Mr. Cameron in 1883, and concluded in 1888, a brief supplement 

 containing a list of the species described or recorded by him elsewhere from Central 

 America having been added last year. The material examined was mostly from 

 Guatemala or the State of Panama, but little from Mexico having been received by us 

 at that time ; hence very few of the numerous Mexican forms of Ichneumonidae, &c, 

 described by North-American writers were represented in our collection. Since then 

 Mr. H. H. Smith has obtained for us a vast number of specimens from Mexico of 

 nearly all the above-mentioned Families ; it is, however, quite impossible for us to deal 

 with this immense amount of additional material now, which would necessitate a fresh 

 study of the entire subject and a revision of the whole work. We are therefore 

 reluctantly compelled to close this Volume as its stands, and trust that Mr. Cameron's 

 "Contribution," incomplete as it must be as regards the total number of species 

 inhabiting the region under investigation, has added considerably to our knowledge 

 of these interesting insects. 



Altogether 1109 species are enumerated, of which 596 are treated as new, the total 

 number for each Family being as follows: — Tenthredinidae, 152, with eighty-three 

 new; Cephidae, one; Siricidae, three, with one new; Oryssidse, two, with one new; 

 Cynipidae, fifteen, with six new ; Figitidae, five, with three new, and two new genera ; 

 Chalcididae, 121, with seventy-one new, and eleven new genera ; Ichneumonidae, 533, 

 with 209 new, and three new genera; Braconidae, 176, with 157 new, and four new 

 genera; Stephanidae, five, with three new; Evaniidae, twenty-three, with sixteen 

 new; Trigonalidae, nine; Pelecinidae, two; Proctotrupidae, forty-three, with thirty- 

 five new ; Chrysididse, nineteen, with eleven new, and one new genus. 



Ed. 



August 1900. 



