XV] ZOO-GEOGRAPHICAL DISTRIBUTION 291 



of the great islands has a rich and, in some respects, characteristic 

 fauna of Odonata. Borneo, although comparatively little worked, 

 can already boast of more species than can be found in the whole 

 of the great Palaearctic region! The total number of Oriental 

 genera slightly exceeds that for the Neotropical, but the number 

 of known species is considerably less. Also, the presence of a 

 large number of Austro-Malayan genera (i.e. genera entogenic 

 both in the Oriental and Australian regions) reduces the proportion 

 of genera peculiar to the region. Out of 136 genera known to 

 occur, 82, or 60 per cent., are peculiar to or entogenic in the 

 region 1 . 



The Oriental region is essentially the home of the Calopterygidae 

 (exclusive of the Neotropical Thorinae). Out of 20 genera and 

 141 species of Epallaginae so far described, 12 genera and 107 

 species are Oriental. Out of sixteen known genera of Caloptery- 

 ginae, nine occur in this region. The glorious development of 



Fig. 153. Hind-wing (17 mm.) of Micromerus lineatus Burm., . 

 India. Original. 



wing-coloration in these Oriental Calopterygidae makes them one 

 of the most striking and gorgeous groups of insects in the world. 

 The tiny Micromerus (fig. 153) is the most reduced Calopterygid 

 genus known. 



The Oriental region parallels the Neotropical in the following 

 points : (i) a great development of Ictinini, of the Ictinus-Series 

 (paralleling the Gomphcndes-Series) ; (ii) the large number of species 

 of the Gynacantha-Series of the Aeschnini; (iii) an exceedingly 

 rich development of the Libellulinae (for lists of genera, see the 

 table) ; (iv) an abundance of Megapodagrioninae and Protoneurinae, 

 (v) a scarcity of Corduliinae. A comparison with the Ethiopian 

 region has already been made. Further striking points about the 

 fauna of this region are (i) the occurrence of the Chlorogomphinae 

 (dealt with under the Palaeogenic Fauna), (ii) abundance of genera 



1 See foot-note on 'p. 286. 



192 



