INTRODUCTION. XV 



material available, and the total nuniber of kinds now presented is reduced 

 through this cause to three Iiundred and seventeen species, distributed 

 through forty-one genera, of which only seven species and two genera 

 are new, though many of the species have not before been noticed in 

 Britain. 



A TABLE OF FAMILIES OF 

 THE ICHNEUMONIDEA (PARASITICA). 



Abdomen emitted from metanotum Evaniidak. 



Abdomen emitted from apex of metathorax. 

 Front wings with discoidal nervures. 

 Terebra rising from near apex of the usually 



deplanate al)domen. 

 Front wing with two recurrent nervures ... Ichneumonidae. 

 Front wing with one recurrent nervure ... Braconidae. 

 Terebra rising from near base of the usually 



compressed abdomen Cvnipidae. 



Front wing with no discoidal nervures. 

 Antennae of S with some ring-like joints ; 



venter emitting terebra Chalcididae. 



(9). 10. Antennae of S with no ring-like joints ; 



anus emitting terebra Proctotrvpidae. 



A TABLE OF SUB-FAMILIES OF THE ICHNEUMONIDAE. 



(4). r. First segment basally contracted ; areolet pentagonal. 



(3). 2. Mesosternum deeply sulcate Cryptinae, 



(2). 3. Mesosternum not sulcate Ichneumoninae. 



(i). 4. First segment not petiolate ; areolet not pen- 

 tagonal. 



(8). 5. Abdomen dorsally deplanate ; post-petiole 

 broad. 



(7). 6. Metanotum not longitudinally costate ; 



terebra exserted Pimplinae. 



(6). 7. Metanotum longitudinally costate ; terebra 



not exserted '{'rvihoninae. 



(5). 8. Abdomen laterally compressed ; post-petiole 



linear Ophioninae. 



The comparative frequency of ijrachypterous and apterous forms in the 

 present sub-family, to which they are nearly confined among the Ich- 

 neumonidae, renders it more essential to notice the conformation of the 

 basal segment than the shape of the areolet ; and it must also be remem- 

 bered, in order to differentiate these parasites from the wingless Braconidae, 

 that in the former the segmentation is flexible and the abdominal joints 

 telescopic, while in the latter the central .segments are connate and rigidly 

 soldered together. An example in point is that of Pezomachus Rosen- 

 haueri, Ratzeburg, which its author bred from the phytophagous 

 coleopteron Cryptocephahis viinutus, Fab., and which is placed by 



