NEUROPTERA 33 



following table of the indigenous Hemerobiidae gives the percentage of species peculiar 

 to each of the islands. 



Of the two Myrmeleonides I have not met with the Eormicaleo perjurus Walk., 

 which is almost certainly becoming extinct ; the other, Eormicaleo wilsoni, is locally 

 common in open places on the lava-flows of Hawaii, where there is a stunted vegetation, 

 and it also is found on other of the islands. Very probably it will prove to be a 

 natural immigrant, and will ultimately be found elsewhere. 



If we compare this table with that of the Agrionidae given on p. 34 it will at once 

 be seen that the percentage of species peculiar to the several islands is much more 

 nearly equal in the Hemerobiidae than is the case with the dragon-flies. In both tables 

 Kauai stands first in the proportion of its peculiar species to the total number found 

 upon it, and this is no doubt due, at least to a considerable extent, to the greater 

 distance between it and the neighbouring island of Oahu, and probably in a lesser 

 degree to its position at the extremity of the forest-bearing islands. The extraordinary 

 richness of Hawaii in species of Anomalochrysa may perhaps point to that island as the 

 spot where these insects first became established. The small percentage of species of 

 Agrion peculiar to most of the islands is probably partly due to their greater powers of 

 flight as compared with the Hemerobiidae, the high percentage of species peculiar to 

 the more remote island of Kauai rather pointing to this conclusion, but it may be that 

 they have been established for a shorter time in the islands than the Hemerobiids, 

 or, even if antecedent to these, they may be less susceptible to the effects of isolation 

 and the changes in environment thereby produced. However that may be, there is no 

 doubt that several of the species of Agrion are at the present time in the process 

 of forming other distinct species, owing to the isolation and change of conditions 

 brought about by individuals having spread to more than one of the islands. 



The Odonata or dragon-flies. The 29 species of Odonata are distributed in 5 genera, 

 but no less than 24 are assigned to the genus Agrion. No doubt they will ultimately 

 be separated from that genus, and will themselves form not less than three distinct 

 genera, but at present it seems better to leave them under that name, as many of the 

 species are difficult, being very variable even in important characters, and some have 

 already formed more or less distinct local races, or subspecies, so that the question as 



' Anomalochrysa riifcscens M'^L., the locality of which is not recorded, is included here as being 

 probably Oahuan. 



S— 2 



