256 Annah of the South African Museum. 



(3) The couditious of the anal vein {A) were not insisted upon by 

 Needham either iu his diagrammatic figures or in liis termiuology, 

 though they are clearly demonstrated iu some of his photographic 

 figures (I. c, pi. xxxi, tig. 1, pi. xxxii, fig. 2). What we are used to 

 name the cubito-aual cross-vein appears, indeed, to be part of the 

 main branch of A itself. The trachea, A, in the larval wing is, in its 

 proximal part, fused with, or indeed very closely applied to, Cu ; wliere 

 it gives up this fusion to beud hindward we have the " cubito-anal 

 cross-vein," and the part of A in the mature wing proximal to this 

 vein appears indeed as a recurrent secondary branch of A — as a kind 

 of " bridge " again. Recently Mr. E. J. Tillyard has developed and 

 illustrated these conditions, and proposed to draw the consequences 

 for the purpose of termiuology (' Proc. Linn. Soc. N.S. Wales,' xxxix, 

 pp. 163 sqq., 1914). 



Needham and otliers, the writer amongst them, have applied the 

 results drawn from the anisopterous wing to the interpretation aud 

 termiuology of the Zygopterous wing. There is no need here to insist 

 on the conditions of the wing base, much less complicated iu the 

 Auisoptera by a minor grade of specialisation of the region between 

 M and Cu (quadrangle instead of triangle and supratriaugular space) 

 and also by the reduction of A to an almost rudimentary state. 

 Applying the anisopterous terms to the Zygopterous wing (from apex 

 to base ; R, Ml, M2, Bs, M3, M4), we have full accordance between 

 the two large groups ; but the conditions of these various branches at 

 their origin, especially iu the nodal region, are far from giving a 

 satisfactory insight into their primitive interdependence (insight 

 which is by no means difficult to obtain iu the mature anisopterous 

 wing). A larval wing of Lestes {I. c, pi. xxxi, tig. 2) gave apparently 

 the key to the question, confirming the full analogy between an 

 anisopterous and a zygopterous wing ; the oblique vein (in the larval 

 and in the mature wing) and the long radio-medial bridge are clearly 

 there, and it might be overlooked that the proximal part of Rs, its 

 origin out of the main branch of R, is altogether absent. But this 

 detail aud other embarrassing disagreements iu tiie Agriouiue wing 

 and iu some of the Calopterygidae might provisionally be accepted as 

 being the consequences of coeuogenetic differentiation by reduction. 

 The writer gradually became sceptical about this entire interpretation 

 of the zygopterous wing on the " Anisopterous " scheme. When 

 discussing the position of Ghlorolestes (in Agrioniuae or Lestinae) with 

 Mr. Herbert Campion, iu consequence of observations first made 

 by this gentleman when studying some genera of Calopterygidae 

 (Philoganga, Bayadera), and discussing analogous questions with Mr, 



