THE ENTOMOLOGIST. 223 
every other tree; and, with huge plants of two other ferns 
(Angiopteris evecta and Asplenium nidus), forms the main 
mass of the vegetation.” And he adds, “I have nowhere 
seen ferns in so great proportionate abundance.” ‘This 
unusual proportion of ferns is a general feature of insular, as 
compared with continental, floras; but it has, I believe, been 
generally attributed to favourable conditions, especially to 
equable climate and perennial moisture. In this respect, 
however, Tahiti can hardly differ greatly from many other 
islands, which yet have no such vast preponderance of ferns, 
This is a question that cannot be decided by mere lists of 
species, since it is probable that in Tahiti they are less 
numerous than in some other islands where they form a far 
less conspicuous feature in the vegetation. The island most 
comparable with Tahiti in that respect is Juan Fernandez. 
Mr. Moseley writes to me :— In a general view of any wide 
stretch of the densely-clothed mountainous surface of the 
island, the ferns—both tree-ferns and the unstemmed forms— 
are seen at once to compose a very large proportion of the 
mass of foliage.” As to the insects of Juan Fernandez, 
Mr. Edwyn C. Reed, who made two visits, and spent several 
weeks there, has kindly furnished me with some exact 
information. Of butterflies there is only one (Pyrameis carie), 
and that rare—a Chilian species, and probably an accidental 
straggler. Four species of moths of moderate size were 
observed—all Chilian, and a few larve and pupe. Of bees 
there were none, except one very minute species (allied to 
Chilicola); and of other Hymenoptera, a single specimen of 
Ophion luteus—a cosmopolitan Ichneumon. About twenty 
species of flies were observed, and these formed the most 
prominent feature of the Entomology of the island. 
Now, as far as we know, this extreme entomological 
poverty agrees closely with that of Tahiti; and there are, 
probably, no other portions of the globe equally favoured in 
soil and climate, and with an equally luxuriant vegetation, 
where insect-life is so scantily developed. It is curious, 
therefore, to find that these two islands also agree in the 
wonderful predominance of ferns over the flowering plants—in 
individuals even more than in species; and there is no 
difficulty in connecting the two facts. The excessive 
minuteness and great abundance of fern-spores cause them 
