58 MR, F. F. LAIDLAW ON 
margin of the mesothoracic half-collar, but not coalescing with the 
brown stripe along its anterior border. Laterally, there isa narrow 
stripe along the second lateral suture continuous over the back. 
Legs: Femora red-brown, tibiz and distal parts black. 
Abdomen rather pale brown, each segment, excepting the first 
two and the last two, having a black ring distally. 1, 2 are 
largely yellow at the sides and have yellow markings dorsally ; ; 
1 this is confined to the posterior half of the segment, except is 
a very fine line extending forwards to the anterior end of the 
segment in the mid-dorsal line. In 2 the dorsal yellow colour 
takes the form of an irregular longitudinal band. On 7 the 
brown of the anterior three-fifths of the dorsum of the segment 
carries a square yellow mark. 9,10 are unmarked, 9 dark brown, 
10 lighter. The latter segment is very short, not half the 
length of 9. 
Anal appendages light brown, the extreme points finely tipped 
with black. In general resembling those of H. smithi Selys, long 
and slender, the upper pair as long as 9, 10 together, the limbs a 
the lower appendage about four-fifths as long. The upper pair 
are straight, their tips hooked downwards to a very trifling extent. 
The limbs of the lower appendage arealso straight, except at their 
apices which have a slight curving upwards, whilst each carries 
at about one-sixth of its length from the apex a small sharply- 
pointed spur, directed inwards at a right angle to the axis of 
the hmb. 
This large and handsome insect represents a genus new to 
the fauna of Borneo, and is one of the most interesting of 
Mr. Moulton’s many “finds” amongst the Odonata of the 
island. ; 
The.specimen will be deposited in the British Museum. 
Subfamily CHLOROGOMPHINE. 
In describing the venation of the species of this subfamily, 
fuse the term “anal loop” to indicate the very definite area 
lying below the cubital space bounded by branches of the anal 
vein ae by An,+Cu,. The name is used in the same sense by 
Needham (Proc. U.S. Nat. Mus. xxvi. p. 733) for Chlorogomphus. 
The loop, as well as the area between Cu, and An, in the hind 
wing, seems liable to considerable individual variation in the 
genus. 
J have figured the penis of Orogomphus dyak (P1. I. fig. 7), 
and would call attention to its close resemblance to that of 
Cordulegaster. The structure of the antenne is also well worth 
remark, 
Ris has noted the occurrence of tibial ridges in the males of 
this subfamily (Ris, Coll. Zool. Selys, ix. p. 9, 1909). These 
ridges, so far as one can judge, are scarcely adaptive structures, 
and their presence would appear to me to indicate a real if 
remote relationship to the Corduline. 
