984 JOVBNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXV HI. 
Other common insect inhabitants of the jungle are termites, butterflies, 
ants and cicadas. As regards the first of these one frequently sees large nests, 
constructed apparently by termites, of a dull grey or black colour and compos- 
ed of a substance resembling papier-mache, either surroimding or projecting from 
a branch of a tree. Butterflies are fairly common both in the jungle and over the 
open grass land. I saw no very striking examples and for the most part the 
individuals seen were of a dull brown colour. Over the open lands these insects 
keep very largely to the tracks made by the cattle during their wanderings. As 
one follows such a track one invariably sees several brown butterflies flitting 
along in front of one near the ground. In this situation they have a high wall of 
grass on either side and it seems not improbable that this habit has been adopted 
as a protection against the high-winds of the monsoon. In places large spiders 
are to be fomid and as one walks through the jungle or between bushes in the 
more open tracts one frequently walks into a tough web in the centre of which 
ifi sitting a gaudy blue and yellow fellow who rapidly beats a retreat as one 
pfxuses to remove the tough clinging strands of her web that festoon one’s face 
and topee. 
As is only to be expected in islands situated within the tropical zone, where- 
ever the coast line is protected coral abounds and fonns great reefs extending 
out, in some cases for very considerable distances, from the shore. 
The debris from these reefs gradually silts up on the shore side and gives rise 
to extensive mud flats, on which mangrove trees can find a hold and can fiourish. 
All around the shores of Nankauri Harbour and Beresford Channel are extensive 
reefs spreading out from the land, and in the land-locked Expedition Harbour 
and Grand Harboiu the growth of coral has extended so far out from the shore 
that a very great portion of their area is now occupied by reefs, while mangroves 
form an almost continuous fringe around their margins. As has been pointed 
out by Tipper.,* “ The general effect of the mangrove swamps is to add gradually 
to the area of the island. The roots of the mangroves act as a sort of catch net 
for sediment washed on to them from the land and also for material brought by 
the tide”, and he might also have added that they act as a basis for the growth 
of rock oysters, which further assist in the process of reclamation. As this pro- 
cess of reclamation extends further and further outwards, the inshore portion 
gradually dries and forms first a damp marine alluvium, on which only mangroves 
can flemish, and finally a dry marine alluvium on which cocoanut palms and 
screw pines find a suitable habitat. Throughout the whole length of the coast 
line of these islands this process is slowly going on, and patches of mangroves are 
spreading out upon the reefs, which in time will become connected into dry land. 
But in addition to this slow process of reclamation, in certain areas a further 
extension of these islands appears to have taken place within geologically recent 
times by the process of upheaval, for on both Camorta and Trinkat Islands I 
have seen masses of what seems to be undoubted reef coral now raised well 
above high water mark. 
I was only able dming our stay in Nankauri Harbour to pay a single visit to 
Trinkat. We sailed across Beresford Channel in the ‘ whaler ’ and landed at 
a large village, Ok-chauka, situated in a little bay on the west side of the island. 
The entrance to the bay is at low water almost completely blocked by an exten- 
sive coral reef, continuous with the main reef that runs along the whole of 
west coast. The landing place in front of the village lies between two 
stretches of mangrove swamp and consists of a small sandy beach, 
intersected here and there by exposed masses of reef-coral, now well above high 
water mark. The village itself stands back a little from the shore and is almost 
hidden in jungle, but from the sea-ward side its position was plainly marked by 
* Tipper,“ The geology of the Andaman Islands, with references to the Nic- 
obars,” Mem. Geol. Survey India XXXV, Pt. 4, p. 15. Calcutta. 1911. 
