860 ON SOME REMARKABLE AUSTRALIAN LIBELLULIN^, iii., 



the female of C, Othello." For purposes of identification I imme- 

 diately forwarded to liim a photograph of my Cooktown female, 

 together with a description, also offering him the use of both for 

 publication in his great work on the Libellulince. In his reply 

 he identifies the Solomon Island insect as C. Othello Q, but most 

 generously refuses to make use of my description and photograph, 

 on the ground that some trouble might arise as to which female 

 should be regarded as the true type, my specimen or the Solomon' 

 Island one. In a later letter, he tells me that he has received' 

 from the Frankfort Museum a small collection of dragonflies from 

 the Aru Islands, containing four males and one female of a 

 Camacinia intermediate between C. Othello and the well-known 

 and widely distributed C. gigantea Brauer, a Malayan species. 

 We are thus able to get some idea of the limits of the range of 

 C. Othello itself. It would be most interesting to know whether 

 it occurs in North-Western Australia or in Timor. It seems 

 fairly certain that it is the descendant of a somewhat early 

 invader from the Indo-Malayan stock, whose isolation has been 

 sufliciently complete and lasting to have produced a very distinct 

 and definite species. Whether it came in by way of Timor, and 

 travelled eastwards to Port Darwin, and thence to Cape York 

 and Cooktown; or whether it came by the easier route of Torres 

 Straits, and then spread westwards, I do not think we have 

 sufficient data to decide. 



It is a most interesting point to notice that, of the great num- 

 ber of Libellulince which form the tropical invasion into Northern 

 Australia, very few indeed shew any variation at all from the 

 forms still found in the Islands. One or two forms deserve sub- 

 specific rank only, in Dr. Ris's opinion — such forms as Agriono- 

 ptera allogenes Tillyard,and A. regalisTiUysLvd; while Australian 

 representatives of Zyxomma obtustcm Albarda, and Orthetriim 

 pruinosum Burmeister, cannot be regarded as more than slight 

 variations from the types. The greater number of species, how- 

 ever, exist absolutely unchanged on both sides of the Straits. 

 We have therefore, in C. Othello, distinct evidence of the anti- 

 quity of the genus Camacinia itself. 



