256 Annals of the South African Museum. 



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

 Needham either in his diagrammatic figures or in his terminology, 

 though they are clearly demonstrated in some of his photographic 

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

 name the cubito-anal 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, Gu ; where 

 it gives up this fusion to bend 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. Eeceutly Mr. E. J. Tillyard has developed and 

 illustrated these conditions, and proposed to draw the consequences 

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

 pp. 163 sqq., 1914). 



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

 results drawn from the anisopterous wing to the interpretation and 

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

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

 Anisoptera by a minor grade of specialisation of the region between 

 M and Cu (quadrangle instead of triangle and supratriangular 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, Rs, MS, M4), we have full accordance between 

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

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

 satisfactory insight into their primitive interdependence (insight 

 which is by no means difficult to obtain in the matui-e auisopterous 

 wing). A larval wing of Lestes (1. c., pi. xxxi, fig. 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 ovei-looked that the proximal part of Rs, its 

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

 detail and other embarrassing disagreements in the Agriouiue wing 

 and in some of the Calopterygidae might provisionally be accepted as 

 being the consequences of coenogenetic differentiation by i-eduction. 

 The writer gradually became sceptical about this entire interpretation 

 of the Zygopterous wing on the " Auisopterous " scheme. When 

 discussing the position of Chlorolestes (in Agrioiiinae or Lestinae) with 

 Mr. Herbert Campion, in consequence of observations first made 

 by this gentleman when studying some genera of Calopterygidae 

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



