194 DEVELOPMENT OF THE WING-VENATION OF ObONATA, 



In the fossil genus, Heterophlebia, about which unfortunately 

 very little is known, there is an attachment of what is probably 

 a long bridge-vein to M.. in the manner of Synlestes. It is quite 

 probable that this fossil stands in somewhat the same relation- 

 ship to Synlestes that Epiophlehia does to Lestes. A careful 

 study of the hindwing-quadrilateral of Heterophlebia should go 

 far towards completing the proof of the Anisoptey^ous ancestry of 

 this group. 



It will be seen that the above study affords us a very satis- 

 factory point from which to start on an entirely new classifica- 

 tion of the Zygoptera. This will be somewhat more fully dealt 

 with in the next section. 



Section C. — The yeneral tracheation of the larval iving in 

 Zygoptera, and its homologies with that of the Anisoptera. 



I have already indicated that my study of the general trachea- 

 tion in Zygoptera is necessarily incomplete, since it is confined 

 to the Agrionid(je. However, in that family I have been able to 

 obtain and study a large number of different genera, a list of 

 which is here given : — 



The list thus comprises nine genera, selected fram five tribes, 

 and represents practically all the Agrionid larvae obtainable 

 within one hundred miles of Sydney. Several of them, indeed, 

 are very rare, and only to be obtained by thorough searching of 

 special localities. 



