706 LIFE-HISTORIES OF AUSTRALIAN ODONATA, NO. Ilf., 



hrevistyla Ramb.; fig.5 of Staurophlebia reticulata Biirm.; and 

 fig.6 is the labium of our new apecies, Phyllo2:>eialia ^yatricia. Of 

 these, 1 belongs to the Cordulegasterince, 2 to the Gomphince, 3 to- 

 the Petalurince, and 4 and 5 to the true jEschnince. 



The most evident thing about them is that No.l is of quite a 

 different type from the other five. In it we have the develop- 

 ment of mental and lateral setae which characterises the Libellu- 

 lince and Corduliince alone amongst the Aniso2)tera\ while the 

 triangular mentum, which when closed is hollow and almost cup- 

 shaped, is also characteristic of these groups. Turning more 

 especially to the lateral lobes, we notice the small movable tooth 

 or hook, and the irregularly serrated inner margin of the lobe^ 

 which is itself broad and well-developed. Such characters are 

 very close to those displayed by the nymphs of Corduliince^ 

 though, in that subfamily, irregular serration of the inner margin 

 is replaced by more or less regular crenation. 



In all the other five, we have a quite different type of labial 

 development. Firstly, the mentum is broad and flat, not much 

 narrowed at the base, and in repose is laid flat against the under- 

 side of the head, Neither mental nor lateral setse are developed. 

 The main attacking strength of the weapon lies in the great 

 development of the " movable hook," which is now a huge tooth. 

 The lateral lobe itself is not broad (except in Petaiiwa), nor does 

 it show on its inner margin any sign of dentation (except in 

 Austrogomphus, which, as in many other Gomphiiue, has a finely 

 serrate margin, while under a lens that of Phyllopetalia may be 

 seen to be exceedingly finely serrate). With all their variations 

 in the shape of the inner lobe, and the lengtli of the large outer 

 tooth, these five labia clearly represent phases of one line of labial 

 development, which is recognised as being peculiar to the family 

 jEscImidce (excluding Cordulegaster for the present). Th^ labium 

 of Phyllo2)etalia itself is peculiar in having the large outer tooth 

 reaching the whole length of the lateral lobe, and apparently 

 jointed, if at all, on to the mentum; while the second and smaller 

 tooth of the lateral lobe appears from behind it. Here is a 

 development unparalleled by any other known genus of Odonata. 



