HYMENOPTERA OF THE HAWAIIAN ISLANDS. 195 



of cultivated plants, and the changes caused in the ground 

 by their cultivation, as well as the introduction o£ Old- 

 World weeds and insects, must, before long, lead to the 

 extermination of many of the native species. This is the 

 more likely to be the case from many of them being of 

 extreme rarity. In fact, according to Mr. Blackburn, one 

 of the most remarkable features in connection with the 

 insects of the Hawaiian Islands is " the extreme rarity of 

 specimens in comparison of the number of species, the 

 common insects being very few indeed, and the rather 

 common ones almost none at alP^"^. We know that many 

 of the animals of oceanic islands have become extinct 

 within comparatively recent times ; and in my mind there 

 is not the slightest doubt that many more will be driven 

 out of existence within the next generation or two. Every 

 endeavour, therefore, ought to be made to induce resi- 

 dents in these remote islands to collect and preserve their 

 insect inhabitants. That good results would be obtained 

 from their doing so can be proved by the remarkable 

 discoveries made by the late Mr. WoUaston in St. Helena, 

 and by Mr. Blackburn in the Hawaiian Archipelago, 

 discoveries of the greatest morphological and biological 

 importance. 



In all countries where the Coleoptera and Hymenoptera 

 have been equally studied, it is found that the latter in 

 numbers equal, if they do not surpass the former, Mr. 

 Blackburn collected in the islands 428 species of beetles, 

 whereof 352 species are at present only known from the 

 Archipelago. As there is not one fourth of this number 

 known of Hawaiian Hymenoptera, I think we may conclude 

 that very many more species have yet to be discovered, 

 even although it may ultimately be proved that they are 

 scarcer relatively than the beetles. 



* Scient. Trans, of the Eoy. Dubl. Soc. iii. p. 202. 



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