INTRODUCTION. XV 



The smaller number of species necessary to be treated of in the present 

 volume has enabled me to devote more space to the consideration of 

 their economy, and the insertion of details in ex/etiso concerning it. A 

 consideration of this, which is a great deal fuller account of the kind than 

 has before been brought together, will enable us to form some very 

 interesting though hardly conclusive theories upon the range of parasitism 

 of any given species, a most fascinating subject, first treated of from the 

 hosts point of view by i\Ir. Ernest A. Elliott and myself in a recent volume 

 of the Transactions of the Entomological Society (if we except the useful, 

 but bare, list of names in Buckler's " Larvae "). Any hypothesis on the 

 subject must be based upon the material available, and the greatest care 

 should, consequently, be employed in notifying the degree of certainty 

 whenever a parasite be recorded as emerging from a specified host ; since 

 it is only too easy to suppose that Lissonota distincta had preyed upon 

 Orchesia ?iiica}is larvae, which had been seen in a fungus, when in reality it 

 had emerged from those of one of the fungus-feeding Lepidoptera, which 

 had escaped observation, unless the dead larva- skins be discovered and 

 recognised. Many, very many, of Ratzeburg's innumerable records err in 

 this manner — in being too superficial — and will ere long be confuted ; 

 nevertheless, where he gives details, no one has done more towards the 

 elucidation of the economy of the Parasitic Hymenoptera. 



The frequency with which the majority of the Pimplinae occur has 

 already been referred to, and this, combined with its comparatively few 

 species has conduced to facilitate their study. The paucity of thoracic 

 sculpture rendered Gravenhorst's general ignorance of it of less moment 

 in this group than in the two preceding and consequently his descriptions 

 are more lucid, especially when used in conjunction with Taschenberg's 

 two papers on the revision of the type specimens in 1863. Holmgren's 

 Monograph of the Swedish species is useful, though he failed in a good 

 many instances, especially in the genus Glypta, to correctly interpret the 

 earlier authors ; and these, with Brischke's Prussian notes and a few from 

 Austria by Tschek and Giraud, were practically all that the British workers 

 of the 'eighties found available. Since that time, however, we have had 

 Thomson's most valuable but not voluminous criticisms, and various con- 

 trii)utions upon the subject from Schmiedeknecht and Kriechbaumcr; and 

 our knowledge is decidedly more advanced than it is respecting any of 

 the other sub-families of the Ichneumonidae. 



That the Lissonotides have any close relationshii) with tiie typical Piin- 

 plides 1 do not for a moment believe ; the Acai-nitides, as at present 

 grouped, are very heterogeneous; and the Banchides are admitedly aber- 

 rant, wherever placed; while the Xoridides, though related to some extent 

 in their thoracic sculpture with Rhyssa, appear worthy of ranking as a dis- 

 tinct sub-family. As a whole the species herein described may be rccog- 



