INTRODUCTION. xliii 



in 1 77 1, no Ichneumonidae of note were brought forward till the publica- 

 tion of Curtis' beautiful work, begun in 1823, which contained, among the 

 Ichneumoninae, descriptions o{ Ichneumon A//o/>os and A/oniya victor on\y. 



The appearance of Gravenhorst's book, in 1S29, stimulated the study 

 here as elsewhere, and was closely followed by the Illustrations, of Stephens, 

 in 1835. This author, refuting the error that "for some untenable 

 reason " a// the species described by Gravenhorst were to be found in 

 Britain, recorded hence just over four hundred and fifty species, many 

 of which had already been noted in his Systematical Catalogue of British 

 Insects, of 1829, and were included in Curtis' Guide to an Arrangement 

 of British Insects, of 1837. Stephens, pretending to no particular know- 

 ledge of the subject, tells us the indigenous species of Ichneumonidae 

 amount to several hundreds, of which he describes thirty-three Ichneu- 

 moninae as new, and sets forth, in tabular form, fifty-four native genera.^ 

 Of his species, about half were included in the Gravenhorstian genus 

 Ichneumon ; but of the remainder only the genera Trogus, Phygadeuon, 

 Cryptus, Stilpnus, Mesoleptus, Tryphon, Exochus, and their immediate 

 allies, were dealt with. Here the sexes are usually described as distinct 

 species, and those afiiliated under a common name often appertain to 

 different kinds. The descriptions are short, structural features are rarely 

 referred to, and no especial distinguishing points are indicated, as was the 

 custom of the period, beyond the mere descriptions. He would indeed 

 be no conscientious systematist who now-a-days relied upon the almost 

 exclusively colour differences therein set forth, for the identification of such 

 variable insects as those under consideration. Such is the only detailed 

 attempt ever made to describe our native Ichneumonidae. 



The middle age of the study, as may be termed the interval between 

 Stephens and Marshall, was not more brilliant than the first. Although 

 Haliday's writings are contemporaneous with those of Stephens, his method 

 of description certainly places him in this period. He was, indeed, as 

 Verrall has said,- " the most perfect describer of a new species or genus 

 in my experience," as his diagnoses of New British Insects indicated 

 in Mr. Curtis' Guide, which appeared in the Ann. Nat. Hist., of 1839, 

 amply demonstrate. Six new genera are here brought forward,^ and about 

 fifty new species shortly but very concisely described. He also first 

 reviewed a few Ichneumonidae, from the Straits of Magellan, in the Trans. 

 Linn. Soc, of 1837 ; and it is to be regretted that his labours extended no 

 further in our particular branch of Entomology. In 1856, there appeared 

 Uesvignes' Catalogue, a synonymic list of those species contained in the 

 British Museum and other collections, with descriptions of fifteen species 

 of Ichneumoninae believed by the author to be new. Herein are brought 

 forward sixty British genera.'* Rather more than seven hundred species of 



1 Of these the great majority are copied directly from Gravenhorst, to which A^riotypiis, Curt. 

 (Walker published no description of it), Lamf'ronota, Hal., and (HjEnicospiltis, Steph , are added; 

 Pachymerus = Collyiid, Schiikl., Kucerus = Eumesius, Westvv., Aloinya = Alomyia, I'anz., Ptltastes = 

 Metof>!us, Panz. Of Trachydcrma, Grav., and Slilboiiota which appears to have never been diagnosed, 

 I know nothing. 



■^ Presidential Address before the Entomological Society, 1900. 



3 Cteiiisciis = Exettttrus, Hart. ; Helictes = Migaslylus, Schiiid., 1839; Peiiope, CUpticus, Aero- 

 dactyla and Lampronota. 



4 The author omits Trachyderma, Odontomerus, Stilbonota, and treats (H)Enicospilus as a 

 sub-genus of Ophinii ; he adds to our list Prist icfi-os and SpkiiictHS, Grav., Trachynotus = Nototrachys, 

 Marsh. Cat., Chyronomoii, l)esv. = Sphecophaaa, Westw., Mactocoleus, Desv.=^ Coleoceiiti us, Grav., 

 Apacticus (sic) and Plalylabus, Wesm., and Pristomerus, Curt.; Desvignes reinstates such recent 

 genera as Listrodromus (cf Wesm. Tentamcn, 1844, &c.), Agruthereiitts (cj. Fiirst. Gattung Pezo- 

 machus, 1850), Triclwmina (c/. Wesm. Des Anomalons, &c., &c.), as sub -genera of, respectively, 

 Ichneumon, Pezomachus, Anomalon, &c., of Gravenhorst. 



