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extreme value in throwing light on the origin of species. 
The Natural History of Oceanic Islands ought, furthermore, 
to be seriously investigated without delay ; for there is not 
the slightest doubt that the introduction of cultivated 
plants, and the changes caused in the ground by their 
cultivation, as well as the introduction of 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 
all.”* 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 residents 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. Wollaston 
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 Hymenoptem 
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 Hymenopiera, I think we may conclude 
that very many more species have yet to be discovered, 
^Scient. Trans, of the Roy. Dub. Soc., Ill,, p. 202, 
