superior PFing of the Hymenoptera. 211 



upon the disc of the wing ; the first of these, which is inclosed be- 

 tween the discoidal and anal nervures, 1 call the first discoidal cell ; 

 the second is that placed between the externo-medial cubital, first 

 recurrent, and discoidal nervures ; the third discoidal cell is that in- 

 closed by the second recurrent, subdiscoidal, discoidal, and first re- 

 current nervnres. The space inclosed between the second recur- 

 rent, subdiscoidal, and cubital nervures, and the apical margin of 

 the wing, forms the first apical cell, and there is a second only when 

 the subdiscoidal nervure extends to the apical margin, by which and 

 a portion of the discoidal cell it is inclosed. 



This completes the description of the nervures and the cells of the 

 wing. I will add a few observations, premising that I have never 

 departed from the nomenclature of my predecessors but where, from 

 the CO- and sub-ordination of the nervures and cells it was requisite 

 to do so to give the description greater precision. 



The costal nervure (Latreille, Kirby, St. Fargeau,) is the radius 

 of Jurine and Gravenhorst. It extends from the base of the wing- 

 generally to the extremity of the radial or marginal cell, and where 

 this is open or incomplete, as in the females of Tiphia, it still extends 

 nearly to where it would have been closed by the radial nervure, or 

 to opposite the termination of the latter, as in Stilbmn, Leucospis, &c. ; 

 but where there is no radial nervure it terminates at the stigma, as 

 in Meria, and it generally dilates near its termination into a round 

 opake spot, which is the stigma of the wing, but which is occasion- 

 ally obsolete. It derives its name from lying parallel when in re- 

 pose with the sides of the insect. 



The post- costal nervure of Latreille and Kirby is the cubitus of 

 Jurine, and occasionally coalesces with the preceding. These two 

 nervures inclose my costal cell, which is however wanting when they 

 unite. In the genus Lyda the interior of this cell is occupied by a 

 nervure springing from its base and terminating in a fork, the prongs 

 of which join the limitary nervures ; sometimes, as in Lophyrus, a 

 transverse nervure cuts it asunder. 



That the true course of the next nervure, the externo-medial, is 

 that which it is described to take in the type, — namely, to run obliquely 

 up to the post-costal in preference to its apparent course by inoscu- 

 lating sometimes at its salient angle with the discoidal and transverso- 

 medial nervures, as in many of the Securifera, the normal and 

 aberrant Ichneumons among the Pupivora, and several of the Hetero- 

 gyna and Fossores, — is proved to be correct by the majority of those 

 tribes, the whole of the Diploptera, and most of the Mellifera, in 

 which it could not take the other course without an evident distor- 

 tion, and is confirmed by its separate and distinct existence in 



