712 ON THE GENUS PETALURA, 



wings. This year I have received from my friend, Mr. E. Allen, 

 of Cairns, a beautiful male, in fine condition, taken near 

 Herberton. With this material to work upon, I was soon able 

 to determine that this enormous dragonfly, without doubt the 

 largest known, is a new species of Petalura, very distinct in 

 many respects from Leach's P. gigantea. 



In this paper I propose to give a careful definition of both 

 species, a good description of P. gigantea being very much needed. 



Firstly as to the position and definition of the family 

 Petaluridoi. The following key will determine it : — 



Division Anisoptera (fore- and hindwings dissimilar). 



I Eyes very close together 1. 



4 Eyes just touching Cor^dulegasterince. 



[Eyes separate 2. 



TTriangles elongated, similar JEschnince. 



\Triangles dissimilar 3. 



(Tvo inferior appendages in male Gomphhuy^. 



2. ^ One inferior appendage in male, superior appendage 



y broadly laminate Petaliiridce. 



THindwings of male rounded at anal angle Libellulince: 



' XHindwings of male angulated (except Hemkoidnlia) Cordidiince. 



Genus Petalura. 



Insects of great size. Head rather small, eyes separated, ocelli 

 in a triangle. Thorax strong and broad, prothorax fairly well 

 developed. Abdomen rather narrow, elongate subcylindrical. 

 Spurs of segment 2 present in male, but not well formed. Appen- 

 dages of male : superior broadl}' laminate, inferior broad, covering 

 the basal portions of the superior beneath. Triangles dissimilar, 

 that of the forewing crossed by two nervules, that of the hind- 

 wing by 1-3 nervules (rarely free). Subtriangle of fore wings 

 reticulated, of hindwings free. Basilar space free; submedian 

 space crossed by one nervule. Pterostigma exceedingly long and 

 narrow. Anal triangle of hindwing in male very long, narrow, 

 divided into three cells. 



