superior fVing of the Hymenoptera. 213 



Larra, Palarus, &c. The cubital nervure originates generally either 

 towards the extremity of the externo-medial near the stigma, or 

 from the centre of its bend upwards beyond the salient angle ; but as 

 a rare exception we find it in Fcenus springing from the salient angle. 

 When the first and second transverso-cubital nervures unite, prior to 

 their junction with the radial nervure, the second submarginal cell 

 is called petiolated, as in Miscophus, Pison, Nysson, Cerceris, &c. ; 

 when this happens to the second and third transverso-cubitals, it 

 is the third submarginal cell which is petiolated, as in Miscus, but 

 this formation is of very rare occurrence. The most important of 

 the secondary nervures is what I have called the discoidal nervure, 

 from the circumstance that no discoidal cell or recurrent nervure can 

 exist without it ; it originates sometimes from the point of union 

 of the externo-medial and transverso-medial nervures, sometimes 

 from the externo-medial itself after it has left the transverso-medial, 

 and sometimes from the latter. It always shows a strong tendency 

 to draw the nervure with which it inosculates outwards towards the 

 disc at their point of contact, and it will be found, in conjunction 

 with the other nervures, to yield very good subsidiary characters : 

 it always returns upon the anal nervure, which it joins near the 

 sinus. At its discoidal angle the first recurrent nervure irtvariably 

 inosculates ; and from near the centre of its posterior return springs 

 the subdiscoidal nervure, upon which depends the existence of the 

 second recurrent. 



I have arranged my order of the discoidal cells differently to St. 

 Fargeau, for I treat them in relation to their consequence ; as we 

 invariably see that where there is no discoidal nervure (which when 

 it exists always incloses the first discoidal cell,) there is never a re- 

 current nervure, which always inosculates with it, forming the ex- 

 terior of the second discoidal cell, and thus consequently subordi- 

 nate to it; and proceeding upon the same principle we find that the 

 third discoidal cell never exists but where there is a subdiscoidal 

 nervure, with which the second recurrent nervure inosculates, form- 

 ing the exterior boundary of that cell. The second recurrent ner- 

 vure stands in the same subordination to the subdiscoidal as the first 

 recurrent does to the discoidal, for it has never a separate existence, 

 although the subdiscoidal nervure is sometimes found alone. It will 

 be thus seen that I have not given the discoidal nervure undue im- 

 portance, as upon its existence hangs that of the first recurrent, sub- 

 discoidal, and second recurrent nervures, and consequently of all 

 the discoidal, submarginal, and apical cells. By not taking this 

 view, which careful investigation proves to be correct, St. Fargeau 

 has unjustly charged Jurine with having erred in saying that a first 

 recurrent nervure exists in his genus Anomalon ; this is evidently 



VOh. I. FART III. R 



