The Heliconide 8 5 
more than twenty different species of butterflies might be 
taken at these spots, the finest being a lovely white, green, 
and black swallow-tailed Papilio, the first capture of which 
filled me with delight. Near the river were some fallen-down 
wooden sheds, partly overgrown with a red-flowered vine. 
Here a large spider (Nephzia) 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 clear- 
ing. 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. I shall 
mention two others. The Heliconide, a tribe of butterflies 
peculiar to tropical America, with long, narrow, weak wings, 
are distasteful to most animals: I have seen even spiders 
drop them out of their webs again; and small monkeys, 
which are extremely fond of insects, will not eat them, as I 
have proved over and over again. Probably, i In consequence 
of this special protection, they have not needed stronger 
wings, and hence their weak flight. They are also very bold, 
allowing one to walk close up to flowers on which they alight. 
There is one genus with transparent wings that frequents the 
white-flowered shrubs in the clearings, and I have sometimes 
advanced my hand within six inches of them without frighten- 
ing them. There is, however, a yellow and black banded 
wasp that catches them to store his nest with; and whenever 
one of these came about, they would rise fluttering i in the 
air, where they were safe, as I never saw the wasp attack 
them on the wing. It would hawk round the groups of 
shrubs, trying to pounce on one unawares; but their natural 
dread of this foe made it rather difficult to do so. When it 
did catch one, it would quietly bite off its wings, roll it up 
into a ball, and fly off with it. Again, the cockroaches 
that infest the houses of the tropics are very wary, as they 
have numerous enemies—birds, rats, scorpions, and spiders: 
