100 
MIMICRY IN INSECTS. 
In considering the area which can contribute to the water 
supply of Northampton itself, it will be necessary to pay much 
attention to the great Nen “ fault,” but that may be fairly left 
for the present. 
I must say that I do not think Agricultural Drainage 
has had much to do with the scarcity of water from the 
Marlstone, because the Maidstone area is well drained 
naturally, but that the diminution is chiefly owing to the 
quantity pumped annually being in excess of the annual 
impounded rainfall which is naturally available. When the 
Northampton Water Company noticed how rapidly the water 
level was sinking in their Billing Road well, they might have 
been sure of the fact that they were draining a reservoir of 
water more rapidly than it could be filled, and that conse¬ 
quently there was a limit to the time it would last. They 
adopted the plan pursued in so many other places, of making- 
fresh wells and new headings, and so increasing the present 
supply with the fact before them that they were only 
the more rapidly exhausting the bed. The result was 
exceedingly manifest in the shortness of water, the supply 
being limited for a long time to three hours a day. 
Agricultural Drainage, by carrying away rapidly very 
much of the water which formerly found its way into the 
rocks below, has no doubt reduced the water-bearing capa¬ 
bilities of many beds, and at the same time helped to cause 
floods in the river valleys. As I said before, I do not think 
the diminution in the Marlstone supply is great on this 
account, but nevertheless it is a factor which must not be 
lost sight of, and there is little doubt that the excessive 
floods in the valleys of Northamptonshire are due in 
part to the excessive drainage of other strata forming 
the uplands. I have spoken of the drainage as excessive 
chiefly because the continuance of wet seasons has caused 
some people to drain as though wet seasons were always to 
be. These lands may correspondingly suffer if we have a 
succession of dry and hot seasons. 
(To be continued.) 
MIMICRY IN INSECTS. 
The beetles and flies of Central America must have learned 
by experience to get out of the way of the nimble Central 
American lizards with great agility, cunning, and alertness. 
But green lizards are less easy to notice beforehand than 
brown or red ones ; and so the lizards of tropical countries are 
