THE ENTOMOLOGIST. 59 
of the smaller ants already affected by the poison, and they 
themselves begin to bite, and in a short time become the 
centre of fresh balls of rabid ants. The sublimate can only 
be used effectively in dry weather. At Colon I found the 
Americans using coal-tar, which they spread across their 
paths when any of them led to their gardens. I was also told 
that the Indians prevent them from ascending young trees by 
tying thick wisps of grass, with the sharp points downwards, 
round the stem: the ants cannot pass through the wisp, and 
do not find out how to surmount it, getting confused amongst 
the numberless blades, all leading downwards. I mention 
these different plans of meeting and frustrating the attacks of 
the ants at some length, as they are one of the greatest 
scourges of tropical America, and it has been too readily 
supposed that their attacks cannot be warded off. ft myself 
was enabled, by using some of the means mentioned above, 
to cultivate successfully trees and vegetables of which the 
ants were extremely fond.”—P. 78. 
Spiders.—“ Near the river were some fallen-down wooden 
sheds, partly overgrown with a red-flowered vine: here a 
large spider (Nephila) built strong yellow silken webs, joined 
one on to the other, so as to make a complete curtain of web, 
in which were entangled many large butterflies, generally 
forest species, caught when flying across the clearing. I was 
at first surprised to find that the kinds that frequent open 
places were not caught, although they abounded on low, 
white-flowered shrubs close to the webs; but, on getting 
behind them and trying to frighten them within the silken 
curtain, their instinct taught them to avoid it, for, although 
startled, they threaded their way through open spaces and 
between the webs with the greatest ease. It was one instance 
of many I have noticed of the strong instinct implanted in 
insects to avoid their natural enemies.”—P. 108. 
Spiders—* * * * “To return to the spiders. Besides 
the large owner and manufacturer of each web, who was‘ 
stationed near its centre, there were on the outskirts several 
very small ones, belonging, I think, to two different species, 
one of which was probably the male of a Thomisus, the males 
in this genus being much smaller than the females. I some- 
times threw a fly into one of the webs: the large spider would 
seize it and commence sucking its blood; the small ones, 
