1886.] MR. BOURNE ON THE FAUNA OF DIEGO GARCIA. 333 
Gannets and Frigate-birds breed at the southern end of the island ; 
and although they are well known to be enemies on the wing, the 
Frigate-bird pursuing the Gannets and compelling them to disgorge 
the fish they have caught, yet they nest close together without 
molesting one another. ‘The Gannets were hatching out on my 
arrival, but the Frigate-birds did not breed during my stay. The 
snow-white Tern, Gygis candida, breeds in considerable numbers ; 
the peculiar situation in which this bird lays its egg has been de- 
scribed by Mr. Forbes in his recent work (‘ Wanderings of a 
Naturalist in the Malav Archipelago’), and I have nothing to add 
to his account. Although Whimbrels, small Plovers, Herons, and 
Sandpipers are numerous on the island, they do not appear to breed 
there. I was assured by the negroes that their eggs were never 
found ; and M. Spurs, a former resident on the island and a natura- 
list of no mean order, tried during a stay of fifteen years to obtain 
the eggs or young of these birds, but without success. 
There are no indigenous Mammalia or Amphibia. A species of 
Gecko (Platydactylus mauritanicus?) is common, and a Mud-Tortoise 
is abundant in some of the marshy pools. The former of these 
reptiles has probably come across in ships from Mauritius; but I 
eannotaccount for the presence of the latter, which is unlikely to 
have been brought over as a pet, for it is abundantly provided with 
stink-glands and emits a most unpleasant odour; it cannot have 
been brought over to serve any useful purpose, nor is it likely to 
have been accidentally imported. Yet, unless it was brought over 
by man, it is difficult to imagine how this animal can have found 
its way over the sea to so distant a spot as Diego Garcia. The 
insect life is not varied; huge cockroaches, mosquitoes, flies, and 
ants swarm everywhere and are a great pest. I found a few nests 
of Termites or White Ants in decayed cocoa-nut stems, but they 
are rare. Of Orthoptera there are two species of Locusta, one of 
Acridium, a Forficula, and a Gryllotalpa. Of Lepidoptera I found 
three species of Nocturnal and one of Diurnal Moths, and I noticed 
a few individuals of Vanessa bolini, and oue individual of (none. 
Three species of Aischna were abundant in the marshes. Of 
Coleoptera I only found four species. Of Myriapods I found a 
Scolopendra, a luminous species of Geophilus, and an Iulus. 
The most remarkable inhabitants of the land are the Crabs. 
Hundreds of Land-Crabs of the genus Gecarcinus are to be found 
in any part of the island, and are a great annoyance to the inhabi- 
tants, for they do great destruction in gardens, and prevent the 
cultivation of the potato or vegetables. There are several species 
of these crabs, one of which attains to a large size and gives 
a formidable nip with its large claws ; it is so conscious of its power 
that it attacks any person who is walking through the grass in 
which it lurks, and is able to give the naked foot of a negroa 
severe wound. Large Hermit-Crabs of the genus Cenobita are 
found, some of them hiding their abdomens in broken cocoa-nut 
shells in lieu of the shells of mollusks, there being but few of the 
latter that are large enough. The close relative of these Canobite, 
