224 WING-VENATION IN ZYGOPTEROUS DRAGONFLIES, 



(i.). Handlirscli's Suborder Anisozyyoptpra becomes untenable, 

 and must be merged into the Zygoptera. The Heterophlebiina^ 

 become Lestidce, all the rest of the forms Calopterygidre. 



(ii.). The crossing of Rs over Mj.., is no longer a character 

 separating the Odonata from all known insects, but only separ- 

 ates the Anisoptera from the Zygoptera. 



(iii.). The dichotomy between Anisoptera and Zygoptera 

 becomes far more pronounced than heretofore. Consequently, 

 the possibility of finding such structures as, for instance, reduced 

 rectal gills in C alopterygidoi, must be regarded not only as very 

 remote, but, if the theory is strictly true, they should not be 

 expected to occur at all. 



(iv.), A name and a notation are required for the extra branch 

 of the media in Zygoptera. Counting the distal end of the main 

 stem, there are five separate branches of the media. We cannot 

 name these Mj, Mg, etc., to M5 without destroying the obvious 

 homologies of M4 and Mg in the Anisoptera with the most basal 

 and most distal branches of M respectively in the Zygop)tera. A 

 name that would suggest the analogy of the extra branch with 

 Rs in the Anisoptera would be the most suitable. I, therefore, 

 propose the special term Zygopterid Sector, with the notation Ms. 

 This notation is clearly the most suitable one, since it allows of 

 the preservation of the homologies of the other branches, and 

 suggests the analogy with Rs which this sector undoubtedly 

 possesses. It is adopted in the figures accompanying this paper. 



As it is of all things the most necessary, both for systematic 

 and biological workers, that the notation for Odonate wing- 

 venation should be speedily and finally settled, the new departure, 

 here instituted, should be criticised at once, and any possible 

 evidence against the new theory should be immediately brought 

 forward. We do not desire change for the sake of change. But 

 we refuse to remain bound to a notation which is clearly both 

 incorrect and misleading, such as the use of Rs in Zygoptera 

 when there is no Rs. In this connection, those who have the 

 opportunity of examining the larval wings of other Zygopterid 

 (a-nd particularly Calopteryyid) genera should do so at once, to 

 see whether they add weight to the new theory or disprove it. 



