698 Mr. R. C. L. Perkins on the 



formed some Colour-groups (e.g. those with red 

 markings) amongst themselves. 



4. A later immigrant species from Asia arrived, a black 



species with dark blue iridescent wings (like and 

 allied to nigripcnnis of to-day). 



5. It became the most abundant and widespread of all 



species occupying all localities (as nigripennis does 

 to-day, excepting in Kauai) on all the islands, 

 except Kauai. 



6. On Kauai only, nigripennis did not remain specifically 



the same, but gave rise to an equally common, 

 allied species 0. radnla, with two yellow bands. 



7. This became and is the dominant species on Kauai, 



and («) may have formed the model for the chief 

 (and almost only) Colour-group on that island, or 

 (b) it is likely that the pale-banded group may 

 have previously been a feature of Kauai, and 

 absorbed the immigrant nigripennis-\\ke insect 

 (which became also structurally modified), or (e) 

 the large series of Kauai forms may have at least 

 developed their dark blue iridescent wings after 

 the pattern of the nigripennis-\ike insect, and it 

 acquired their bands. 



8. In the open country of all the islands (excepting 



Kauai) whether above or below the forest, a large 

 number of species remain, which probably most 

 nearly show the superficial appearance of the 

 original immigrant Odynerus. 



9. This open country is that which would always 



(from the nature of the avifauna) have been either 

 devoid of insectivorous birds or very sparsely 

 frequented by them. 



10. On Hawaii, the big island, the tendency is decidedly 



to one uniform condition of blackness and the 

 formation of a single group — the pale-banded 

 forms tending to lose the bands, or having quite 

 lost them in the female sex ; the red-marked species 

 having the red marks diminished, faint or dull, 

 as compared with the nearest allied species on the 

 neighbouring islands. Hawaii is very rich in birds. 



11. Except on Kauai, the ancestral character of the 



yellow bands is confirmed by their retention by 

 those species which are least peculiar as compared 

 with foreign forms, and by the fact that almost 



