214 Mr. Shuckard on the superior Wing of Hymenoptera. 



the fact, and St. Fargeau himself is distinctly in error, for otherwise 

 in this genus the cubital nervure would originate from the discoidal, 

 which can never be the case, as it is proved by analogy invariably 

 to arise either from the base of the stigma, or just below from the 

 exterior of the externo-medial nervure, which in that genus, and 

 indeed throughout the normal Ichneumons, the anterior portion of 

 the cubital nervure is deficient, thus merging the second discoidal in 

 the first submarginal cell. This is the case also in the genus Oxy- 

 belus amongst the Fossores ; in Paxylomma, Chelonus, several Mi- 

 croctoni, and Aphidii, amongst the aberrant Ichneumones ; in Helorus 

 amongst the Oxyiirites ; and by a peculiarity in this genus the above 

 two cells are not separated from the externo-medial cell, owing to 

 the upper half of the externo-medial nervure between its salient 

 angle and the stigma falling back upon the anastomosis of the re- 

 current nervure with the salient angle of the discoidal nervure, thus 

 inclosing a triangular portion of the second discoidal cell. And 

 that this is correct is evidently proved by the existing remainder of 

 that first portion of the cubital nervure, found most strongly in the 

 approximate genus Ophion, as well as in Tragus, Echthrus, Rhyssa, 

 and the majority of the genus Ichneiimon ; for there is decidedly no 

 anomaly of structure in this tribe, but merely the suppression of that 

 portion of the cubital nervure which would have formed half of the 

 first cubital cell at the junction of the first recurrent nervure with it. 

 The discoidal cells I have named in reference to their position and 

 existence, being influenced by the discoidal nervure, and the apical 

 cells from their situation upon the apical margin. 



The following I consider their relative value in point of organization. 



1 . The primary nervures in their consecutive order. 



2. The radial or marginal nervure. 



3. The discoidal nerv^ure. 



4. The first recurrent nervure. 



5. The cubital nervure and its transverso-cubitals. 



6. The subdiscoidal nervure. 



7. The second recurrent. 



And that this is their true natural gradation I feel fully persuaded, 

 and willingly invite the fullest, but at the same time candid and un- 

 prejudiced, investigation. I am fearful that the repetition of terms 

 (which was important to the full elucidation of my views) may have 

 proved tedious; I will therefore no longer detain you upon this subject, 

 but will defer its practical application to our next meeting, when I 

 hope to prove more fully the extent of its value, and which I expect 

 to render more interesting than the present paper could possibly be, 

 by the intercalation of desultory remarks upon several genera. 



