6 PROCEEDINGS OF THE NATIONAL MUSEUM, — you. 62. 
9. Median space with cross nerves. Arculus muchangled......... Amphiaeschna. 
Median space without cross nerves......-..--------------- ...... Aeschna, 
10. Median space with cross nerves. Size moderate...........-.-.-. Heliaeschna. 
Median space free. Size very large. ....-.......-...-..-.-.-- Tetracanthagyna. 
These genera may be grouped as follows: 
BRACHYTRON GROUP. AESCHNA GROUP. 
Jagoria. Anax series: Anax. 
Tinaeschna. Anaciaeschna. 
Caliaeschna ? [amphiosctna 
Cephalueschna. Aeschna series. - -. . Aeschna. 
Brachytron series . .( Periaeschna. bee 
Planaeschna ? Tetracanthagyna. 
Austroaeschna. Gynacaniha series: Gynacantha. 
I do not use the term Boyeria series for Jagoria and Linaeschna, 
because it seems to me that such a series does not exist, i. e., that 
the various genera with unforked radial sector and straight supple- 
ments can not all be referred to a single series. On the other hand 
I think a good case can be made out for a Brachytron series, as it 
would appear that all the genera here referred to that series and 
others that are nonregional are closely related to the typical genus 
Brachytron. 
The suppression of the genus Hemianaz is dependent on the 
amount of importance one attaches to the characters which separate 
Hemianax ephippiger from the species of Anaz. Personally I think 
them of not more than specific value. 
The inclusion of Anaciaeschna in the Aeschna series rather than 
with Anaz is again a matter of opinion and of convenience. The 
genus is decidedly annectant. 
Lastly in transferring Heliaeschna and Tetracanthagyna from the 
Gynacantha series to the Aeschna series I have been guided largely 
by the extreme differentiation in the genus Gynacantha of the dentig- 
erous plate. That of Heliaeschna, so far as I know it, and of 
Tetracanthagyna seems to me to stand nearer to Aeschna. There is 
of course nothing decisive in the venation. 
NOTES ON LARVAE. 
The characterization of the main groups in the above table is 
largely drawn from Tillyard’s Biology of Dragonflies.? Since writing 
it and the preceding part of this paper I have been able to secure 
some additional imformation on one or two points of interest. This 
had been derived in part from an examination of larvae of two spe- 
cies of Cephalaeschna (2) from the Himalaya, identified by exami- 
nation of the venation, and from larvae of Aeschna ornithocephala 
MacLachlan from the same part of the world. 
2The Biology of Dragonflies. Cambridge University Press, 1917, Cambridge, Eng. 
