22 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62, 
Length of abdomen 49 mm., of hinder wing 48 mm., of anal 
appendages 6.5 mm., and of pterostigma 4 mm. 
GYNACANTHA DOHRNI Kruger. 
Plate 1, fig. 5. 
The next three species, all recorded from Borneo, may be regarded 
as forming a natural group, characterized by the great widening of 
the base of the abdomen, which when viewed from above is approxi- 
mately circular in outline whilst the narrowing of the third segment 
is extreme; by the great size of the auricles, by the absence of a T- 
shaped mark on the frons, and by the brown color of the legs. The 
upper anal appendages of the males are very long and slender, not 
less than four times as long as the lower appendage. Of the three, 
dohrni from Sumatra, Java, and Borneo has the base of the hinder 
wing tinged with brown in the subcostal and cubital spaces as far as 
the level of the first antenodal nerve, whilst the innermost well of 
the anal triangle is also tinged with the same color. 
The female has similar markings at the base of the hinder wing, 
but in this sex the whole wing is richly and evenly suffused with 
golden-brown. The anal appendages of the male have a small in- 
ternal subbasal projection, and the pointed apices are directed almost 
straight backwards. The appendages, upper pair, have a length of 
7.2mm., whilst the wings are about 43 mm. in the male, and 47 mm. 
in the female. 
GYNACANTHA DEMETER Ris. 
G. demeter from Borneo is very similar. The male has the wing 
base hyaline or very lightly suffused with yellow. The upper anal 
appendages of the male are similar to those of dohrni, but shorter, 
only 6 mm. in length, with the more sharply acuminate apices directed 
rather laterally. The female in this species also has the wings strongly 
suffused with brown, which in some specimens deepens in tone be 
tween the nodus and pterostigma. In size this species approximates 
closely to the last. 
GYNACANTHA MACLACHLANI Kruger. 
G. maclachlani, the third of the group, has the upper anal append- 
ages of the male without a subbasal projection, about 6.5 mm. in 
length, a little more dilated apically than is the case in the two 
previous species, which it resembles closely in size. Kruger in his 
original account gives the length of the abdomen at 44-46.5 mm. 
and of the hinder wing 45 mm. The pterostigma seems to be smaller 
than in either dohrni or demeter, 3 mm. as against 3.5 mm. (Martin 
gives New Guinea as a habitat for this species, but as his measure- 
ments are very different from those given by Kruger I can not feel 
sure that he is dealing with Kruger’s species. Ris rejects his record 
