336 MONOGRAPH OF THE GENUS SYNTHEMIS 



There is also a corresponding difference between the larval 

 forms (so far as they are known). The nymph of S, Jiavoterminata 

 is small and of rather slender build, with a small projecting 

 frontal rectangular plate, fringed with small hairs; that of S. 

 guttata is of stouter build, and has a much larger almost semi- 

 circular projection or plate standing out from the front; those of 

 S. eustalacta, S. macrostigma, and S. regina are of stout build, 

 but possess only a row of hairs on the front and not a projecting 

 plate (see Plate viii., fig. 2, S. eustalacta; fig.5, S. guttata). The 

 fovir species comprising the genus Metathemis are so closely allied, 

 that I have no doubt this frontal plate will be found in the 

 nymphs of the other three, and will form an excellent generic 

 diagnostic for the larval forms. 



The classification proposed may now be exhibited as follows:— 



(Front small, abdomen narrow cylindrical, membran- 

 ule absent • Choristhemis, n.g. 

 Front large, abdomen of variable width, membran- 

 ule present 2. 



'Superior appendages of male short; female without 



ovipositor Metathe77iin, n.g. 



Superior appendages of male long and wavy; female 



with, at least, a rudimentary ovipositor Synthcmis (s.str.). 



And, for the nymphs : — 



'Small nymphs of slender build; front with a small 

 projecting rectanyiilar plate, fringed with small 



hairs ... Choris(hemis,n.g. 



Larger nymphs of stouter build 2. 



Front with a conspicuous semicircular projecting 



plate Metathemis, n.g. 



Front without a plate, but with a row of hairs Synthemis (s.str,). 



I now pass to the systematic description of the species, arranged 

 in the proposed genera. Where the life-history has been studied, 

 the details of it and the description of the nymph are given under 

 each species. The descriptions of the imagines are taken from 

 freshly killed specimens, and are made as short as is consistent 

 with a full determination of specific differences. 



1. 



