428 ON THE NEW GENUS AUSTROGYNACANTHA, 



ong as the tongue (Plate v. figs. 4, 5). (4) 6-7 rows of very small 

 cells. (5) 2-3 hypertrigonals in hind wing. 



Karschia and Austrogynacantha apparently agree in the shape 

 of the abdomen at segment 3, and also in the curvature of the 

 nodal sector under the pterostigma. 



Austrogynacantha and Gynacantha (s.str.) agree in the shape of 

 the front and eyes, and practically also in the form of the mem- 

 branule, which, though small in both, can scarcely merit the 

 summary dismissal implied in the "presque nil" of Rambur 

 (Plate v. figs.6, 7). 



The following key will now serve to distinguish the new genus 

 and to show its correct position in a classification of the Aus- 

 tralian genera of the subfamily Aeschnince. 



rHindwing of £ without an anal triangle (i.e., post- 

 costal margin quite rounded) , 1. 



j Hindwingof £ with an anal triangle (i.e., postcostal 



margin more or less angulated) 2. 



, \ Inferior appendage of $ truncated Anax. 



\ „ ,, ,, triangular Hemianax. 



<2 / Subcostal vein prolonged beyond nodus Teltphlebia. 



I ,, ,, not prolonged beyond nodus 3. 



„ K Basilar space reticulated Caliaeschna. 



' » ti free 4. 



. ( Subnodal sector not bifurcated (absent fromAustralia) 



' ,, ,, bifurcated 5. 



f. \ One row of cellules under fork Austroaeschna. 



3-7 rows ,, ,, ,, 6. 



■ Seg.10 of 2 rounded below, carrying small spines Aeschna. 

 6< ,, ,, prolonged below into a tongue armed 



( with two distinct prongs 7. 



Anal triangle of J 1 fairly broad, 3-celled; post- 



i costal margin strongly angulated Gynacantha. 



j Anal triangle of $ very narrow and long, If.-celled; 



postcostal margin scarcely angulated at all... Austrogynacantha. 



Austrogynacantha heterogena. 



Gynacantha heterogena Selys MSS. (§). 



£. Total length 59-60 mm.; abdomen 46 mm.; fore and hind- 

 wings 37-38 mm. Wings: costa brown, subcosta and nodus 



