INTRODUCTION. 



XXXV 



DETAILS OF THE METATHORAX. 



This figure represents a postero-dorsal view of the metathorax, the 

 various areae of which, outUned by elevated costae, though not always 

 stable, form valuable characters for discrimination, especially in the two 

 first sub-families, in which they are more fully developed. In this figure, 

 I is the basal area, always very distinct in the Joppides and usually obsolete 



or wanting in the Ichneumonides ; 2 is 

 the areola (area superomedia), behind 

 which, sloping downwards, is (3) the 

 posterior orpetiolar area. From this, 

 the postero-intermedial (3^?) and the 

 postero-external (3/^) areae are some- 

 times discreted, and to its apex (at 10) 

 the petiole is attached. The upper 

 lateral areae are very often also centrally 

 discreted, in which case the anterior 



(4) is the external, and the posterior 



(5) the dentiparal areae. From the 

 apex of the latter rise the thoracic 



These two areae 



Metathorax. — i, basal area ; 2, areola ; 3, 

 posterior or petiolar area ; 317, postero- 

 intermedial areae ; 3ft, postero-external 



areae ; 4, external areae ; 5, dentiparal . , 



areae ; 6, spiracular areae ; 7, lateral or SpineS Or apophyses. 



£"ies^"i''o^ 'ape'J"'''''"'"''^' "''^'' ' ^' ^^^ Centrally divided by the costula, a 



term confined to this particular ridge. 

 The spiracular areae (6) bear the metathoracic spiracles (9), which are 

 of variable shape (the anterior portions of the thorax also bear obscure 

 spiracles, not referred to in descriptions). The lateral or pleural areae (7) 

 are sometimes distinct from the juxta-coxal (8). Of these areae, the areola 

 is the most important and constant, at least some part of it being present 

 when all other areae, through the razing of the costae, have become 

 obsolete or wanting. Its apical ridge has been especially employed by 

 Forster in grouping the Pezomachi, &c., and it is also a conspicuous 

 feature of the Cryptids and Pimplinae. Ashmead has founded genera 

 u[)on the confluency of the juxta-coxal and pleural areae, and in most 

 cases the apical central costae are wanting. 



DETAILS OF THE WINGS. 



The wings of the Ichneumonidae at first sight appear so uniform that, 

 with the exception of the points already referred to, the older authors ^ 

 gleaned but few distinctive points therefrom. When these jt'ere indicated, 

 original names were almost invariably applied to them, whether oihers had 

 been already known or not, and in this manner the nomenclature of the 

 nervures and cells has become considerably involved, and in some cases 

 chaotic. Modern authors - have been hardly more uniform, and it seems 

 advisable to here attempt some sort of synonymy of these bewildering and 

 often misleading terms. Gravenhorst named all the cells, but few of the 



1 C/. Gr. I. K. i., t. I ; Wesin. Nouv. M^m. Ac. Brux., 1844, f. i ; Bill. Ac. Brux., 1849, p. 117; 

 Holmgr. Sv. Ak. Haiidl., 1855, t. ix. ; Ichn. Suec. i., ff. i et 2 ; Forst. Verli. z.-b. Gas., 1868, pp. 874-6, 

 Taf. X.; &c. 



■J Cf. Bridg.-Fitch, Entom., 1880, pi. i., f. 2; lib. cit., 1882, p. 279; Bifinell, Trans. Devon. Assoc, 

 1898, p. 46 ; Thorns. O. E., 531, ff. i-io ; Berth. Ann. Soc. Fr., 1895, pi. iii., ff'. r-6 ; Slc. Also compare 

 Marsh. (Braconidae). Trans. Ent. Soc, 1885 ; Saunders, Acul. Brit. Isles, 1896, Struct, pi., f. i ; 

 Cameron, Phytoph. Hym., 1882-93 ; &c., &c. 



