S12 Mr. W. E. Shuckard's Description of the 



Nenrospora *. The extemo-medial cell inclosed by it is alwajns a 

 variously modified transverse triangle. 



The transverso-medial nervure invariably inosculates at the sa- 

 lient angle of the externo-medial when the discoidal nervure springs 

 from the same point or from the transverso-medial : but always 

 when the discoidal nervure springs from the exterior of the externo- 

 medial, which it generally distorts, as will be hereafter shown, the 

 transverso-medial is regular, and generally directly transverse ; this 

 formation occurs in Larra, Tachytes, Miscophus, Astata, Crabro, &c. 

 In the Diploptera it is placed much nearer the base of the wing than 

 in the other tribes. The cell, my interno-medial, to which this 

 forms the closing apex is crossed transversely, and divided into two 

 by a pseudo-nervure in the genus Lyda. 



The anal nervure generally joins the posterior margin of the wing 

 at its apex, where it terminates at the sinus ; but in Sphex and some 

 other genera its positive junction is obsolete, being merely slightly 

 traced, and sometimes this union is entirely obliterated, as in Scolia. 



The anal cell is occupied in many of the Securifera by either an 

 undulating nervure as in Cimbex, Pachylosticta, Sirex, Tremex, &c., 

 or by merely a transverse one as in Cephus, or by both as in Lyda. 



These cells, to which I have given individual names, derived from 

 their limitary nervures, are what constituted collectively Jurine and 

 St. Fargeau's brachial cells, and Gravenhorst's humerals, and the 

 basal cells of other writers. The nervures above described, by which 

 they are inclosed, I consider the primary ones of the wing, as the 

 existence of the rest is wholly dependent upon them. 



The rest comprise the secondary nervures. 



The marginal cell is cut transversely, chiefly in the Terebrantia, 

 by one or two nervures which I call the transverso- radial ; they can 

 be named only in the order of their succession, their separate and 

 distinct existence not being dependent upon their position or inos- 

 culation. We have but one instance of there being two, viz., in the 

 genus Xyela : when there is but one transverso-radial nervure across 

 the body of the cell there are two cells, as in many of the Securifera ; 

 but when this transverse nervure is removed closely to the apex of the 

 radial cell, the latter is then called appendiculated, whether the por- 

 tion thus separated be open, as in Astata, or closed, as in Hylotoma, 



* This insect, which is unique in my own cabinet and as yet undescribed, is evi- 

 dently allied to Paxylomma, Breb., the Plancus of Curtis. Their true situation ap- 

 pears to me to be between the Oph'iones and Adsciti, where PcleciinisaxiA. Stephanus 

 ought to come, for P elecinus h^s ceiiaXnly no connexion with the Evdniales, nor are 

 the latter in their proper place unless the relative situation of the groups which fol- 

 low be much remodelled. 



