BY B. J. TILLYABD. 427 



Of these differences, I consider Nos. 2, 5, and 6 of primary 

 importance, and sufficient in themselves to place Austrogynacantha 

 absolutely apart from Gynacantha (s.str.). The form of the 

 abdomen may be seen in the Plate (fig.1); the remarkable forma- 

 tion of the anal triangle of the male, giving it practically a 

 rounded hindwing, infig.7; while that of G. Rosenberghi is shown 

 in fig. 6. The difference in the curvature of the nodal sector may 

 be studied in figs. 8 and 9. 



The differences 10-12 may be directly attributed to the differ- 

 ence in size between the insects; while differences in the append- 

 ages and pterostigma cannot be pressed, for we find an amazing 

 amount of variation in these respects in the Aeschnidce. For 

 instance, the species of the genus Austroaeschna show remarkable 

 variety in the size and shape of the appendages of both sexes; 

 while actually in the individual specimens of A. unicornis Selys, 

 the pterostigma shows a considerable variation in length. 



It is now necessary to indicate the differences between Karschia 

 Forster, and Austrogynacantha Tillyard. This can only be done 

 by a comparison of the females, the males of Karschia being still 

 unknown. Furthermore, the position of Karschia in any classifica- 

 tion of the Aeschnidce, as well as its exact relation to Gynacantha 

 (s.str.) cannot be accurately determined until the males are 

 forthcoming. 



Kabschia Forster (K. cornutaQ Foerster). — (1) Upper edge of 

 front interrupted in the middle, more or less projecting in an 

 angle. (2) Eyes strongly arched above, not depressed. (3) 

 Spikes of the terminal fork of the tongue-shaped abdominal 

 appendage on seg. 10 only half as long as the tongue. (4) Between 

 nodal and principal sectors, near end of wing, only 5 rows of 

 cells at the most. (5) 3-4 hypertrigonals in hindwing. 



Austbogynacantha Tillyard (G. heterogena 9). — (1) Upper 

 edge of front not interrupted in the middle, straight or very 

 slightly curved as in Gynacantha (s.str.). (2) Eyes weakly arched 

 above, as in Gynacantha (s.str.). (3) Spikes of the terminal fork 

 of the tongue-shaped abdominal appendage on seg. 10 almost as 



