ART, 21. DRAGONFLIES OF BURMA AND LOWER SIAM—LAIDLAW,. 17 
and at least three times as long as the lower appendage. ‘The 
Bornean species simplicia Karsch has the upper anal appendages 
straight, flattened dorsoventrally, and shaped like a hunting knife. 
The length of the hinder wing is about 45 mm. 
Lastly, wninervulata Martin, recorded from Borneo, Engano (Suma- 
tra), and now from Burma, is distinguished from the other Asiatic 
species by its more rounded wings, by the single cross nerve in the 
median space, and by the upper anal appendages of the male, which 
resemble those of the African species weelet Martin, being broad and 
bladelike with semicircular infolding of the inner margin and out- 
curved apex. 
HELIAESCHNA UNINERVULATA Martin. 
One male (in poor condition) Burma. R. A. Earnshaw, collector; 
collection E. B. Wilhamson. 
The pterostigma is small, and in this specimen well braced. Mar- 
tin’s photograph (of a female) shows the pterostigma of the hinder 
wing unbraced. 
The coloring of the specimen is entirely faded, and the abdomen 
in fragments. 
Length of hinder wing 41 mm., of pterostigma 2.5 mm. 
LIST OF ORIENTAL SPECIES OF THE GENUS HELIAESCHNA. 
. H. gladiostyla Martin: The Celebes. 
. H. filostyla Martin: The Celebes. 
. H. idae Brauer: Borneo. 
. H. crassa Kruger: Borneo. 
H. simplica Karsch: Borneo. 
H. uninervulata Martin: Borneo, Engano ‘Sumatra), Burma. 
oon & HH 
Genus TETRACANTHAGYNA de Selys. 
Plate 1, fig. 4 
The species comprised in this genus, probably the largest and 
bulkiest of all living dragonflies, seem to be a luxuriant development 
of the same stock as that from which Heliaeschna is derived. Not 
only is there a close similarity between the dentigerous plates of the 
two genera, but there is also a general resemblance in the venation, 
and both have at least in certain cases an unbraced pterostigma. 
The venation of Tetracanthagyna is certainly the denser, a feature 
almost certainly connected in this case with great size, and acquired 
secondarily. The males do not show narrowing of the abdomen at 
the second and third segments, this is perhaps a primitive character. 
No species has been recorded from Burma, but the known range 
of the genus includes Tonkin, the Malay Peninsula, Borneo, and 
Sumatra, and it has been my good fortune to capture a single exam- 
ple of the genus, a female of 7. brunnea MacLachlan, in Kelantan in 
