336 Records of the Indian Museum. [Vol. VIII, 



study of these groups of Odonata, uot only for Burma but of a 

 great part of the whole Oriental Region, reviewing as he does 

 species allied to those of Burma, but inhabiting neighbouring lands. 



None the less oui knowledge of the dragonflies of these coun- 

 tries is still so imperfect that it is of little use to discuss the geo- 

 graphical relationships of the area. I may briefly state my own 

 belief on the subject is that the fauna of Burma as of other Indo- 

 Malayan countries is the result of the intermingling of several 

 groups — the re-ult of several irruptions into the territory at differ- 

 ent epochs. Such groups for want of a better term may be called 

 ' strata.' Much field work and systematic study is necessary 

 before it will be possible to distinguish one ' stratum ' from another 

 and to determine anything of its geological history. 



Other references to literature will be found at the end of the 

 paper. 



Systematic. 



LIBELIvULIDAE. 



LIBELLULINAE. 



1. Amphithemis vacillans, de Selys. 



1 o* (immature), Assam {H. Stevens). 



2 cf <^ Kachin Hills, Upper Burma {Capt. Topin). 

 Length of abdomen 23 mm. 



,, hind-wing 27 mm. 



Both of the specimens from Upper Burma are fully adult, 

 and both have the third abdominal segment powdered with bluish- 

 white bloom, which gives the insect a striking appearance. 



2. Lyriothemis acigastra (de Selys). 



2 cf cf , 1 9 {i cf very immature). 



The adult male and the female have been examined for me by 

 Dr. Ris, who has kindly compared them with de Selys' actual type 

 cf . He has found them to be identical therewith ; but not with the 

 specimens described and figured in his Monograph under the name 

 L. acigastra (190Q). The latter specimens, which belong to Mr. 

 Morton, represents an undescribed species. 



3. Orthetrum sabina (Drury). 



I cf Kawkareik to Third Camp, Amherst district, Lower 



Burma, 21-xi-ii (F. H. Gravely). 

 I 2 Kobe, 400 ft., Abor Expedition (S. W. Kemp). 



4. 0. glaucum (Brauer). 



4 cf cf adult, I o?' immature, i 9 Kachin Hills, Upper 

 Burma {Capt. Topin). 

 One male has a cross-nerve in the triangles of both hind- wings, 

 another has one triangle crossed and one free. 



5. 0. pruinosum neglectum (Ramb.). 



3 cf cf , I 5 Kachin Hills, Upper Burma {Capt. Topin). 



I cf Moulmein, Lower Burma, i6-xi-ii (F. H. Gravely). 

 I cf Upper Assam {H. Stevens). 



