16 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62, 
pterostigma. The anal appendages are said to be very long, shaped 
like laurel leaves. The species occurs in Tonkin and Java; and will 
doubtlessly be found in intermediate territory. 
Genus HELIAESCHNA de Selys. 
Plate 1, fig. 3. 
Six species of the genus are oriental and three Ethiopean. Forster 
has proposed to create a distinct genus for the Asiatic species with the 
name Malayaeschna. His reasons are that the latter have a longer 
triangle and wings more pointed relatively than the African spe- 
cies; and that whilst Malayaeschna has a four-toothed (or six-toothed) 
dentigerous plate the African Heliaeschnas have a two-pronged plate. 
It is worth remark that De Selys in his generic definition describes 
the dentigerous plate of fuliginosa, the genotype, in identical terms 
with that of Gynacantha. 
The venational characters do not seem to be of much weight, and 
as the female of several of the species is unknown I do not here adopt 
Forster’s genus, though I think it quite likely that his suggestion will 
prove ultimately to be well advised. The species of this genus ap- 
pear to bear a fairly close resemblance to those of Gynacantha, and 
there is some justification for regarding them as representing an an- 
cestral form of the latter genus. We may count the cross veins of the 
median space as a primitive character, and it is quite reasonable to see 
in the dentigerous plate a type of structure from which the highly 
specialized Gynacantha fork may have arisen. But the problem of 
Periaeschna must not be forgotten in this connection. 
Another characteristic is the absence of the brace to the ptero- 
stigma in some of the species at any rate (idae, fuliginosa) whilst in 
uninervulata it is usually present. 
Of the six species recorded from Asia, two H. gladvostyla Martin 
and H. filostyla Martin are from the Celebes. They are both un- 
known to me, but seem related to H. idae Brauer and to H. crassa 
Kruger from Borneo. Of these two latter the first is somewhat the 
larger, and has the hinder wing 54 mm. long and the abdomen 55 
or 56 mm. in length, whilst crassa has measurements for the same 
structures, 50 mm. and 50 mm., respectively. The female of idae 
has a brown stripe occupying the subcostal space and running from 
the base of the forewing to the nodus, whilst a transverse band of 
lighter brown extends across the wing between the nodus and ptero- 
stigma. The hinder wing has only a dark basal mark in the costal 
and subcostal spaces extending to the level of the arculus. 
These four species, of which I have seen idae only, seem to be re- 
lated to each other in possessing rather pointed wings, and in the 
shape of the upper anal appendages of the male, these latter being 
in each case very long and slender (in idae they are 7.5 mm. long) 
