3. BUTTERFLIES, ANTS, AND SPIDERS
OF BRAZIL.

The large and brilliantly-coloured Lepidoptera bespeak the zone they inhabit far more plainly than any other race of animals. I allude only to the butterflies; for the moths, contrary to what might have been expected from the rankness of the vegetation, certainly appeared in much fewer numbers than in our own temperate regions.

I was much surprised at the habits of one butterfly, not uncommon, and generally frequenting the orange groves. Although a high-flier, yet it very frequently alights on the trunks of trees. On these occasions its head is invariably placed downwards, and its wings are expanded in a horizontal plane, instead of being folded vertically, as is commonly the case. is the only butterfly that I have ever seen that uses its legs for running. Not being aware of this fact, as I cautiously approached with my forceps, the insect more than once shuffled on one side just as the instrument was on the point of closing, and thus escaped.

This

But a far more singular fact is the power which this species possesses of making a noise. Several times when a pair were chasing each other in an irregular course, they passed within a few yards of me, and I distinctly heard a clicking noise, similar to that produced by a toothed wheel passing under a spring catch. The noise was continued at short intervals, and could be distinguished at about twenty yards' distance.

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A person, on first entering a tropical forest, is astonished at the labours of the ants. Well-beaten paths branch off in every direction, on which an army of never-failing foragers may be seen, some going forth, and others returning burdened with pieces of green leaf, often larger than their whole bodies.

A small, dark-coloured ant sometimes migrates in countless numbers. One day, at Bahia, my attention was drawn to many spiders, cockroaches, and other insects, and some lizards, rushing in the greatest agitation across a bare piece of ground. A little way behind, every stalk and leaf was blackened by a small ant. The swarm having crossed the bare space, divided itself, and descended an old wall. By this means many insects were fairly enclosed, and the efforts which the poor little creatures made to extricate themselves from death were wonderful.

When the ants came to the road, they changed their course, and in narrow files reascended the wall. I placed a small stone so as to intercept one of the lines; whereupon the whole body attacked it, and then immediately retired. Shortly afterwards another body came to the charge, and having again failed to make any impression, this line of march was entirely given up. By going an inch round, the file might have avoided the stone, and this, doubtless, would have happened if it had been originally there; but having been attacked, the lion-hearted little warriors scorned the idea of yielding.

Certain wasp-like insects which construct in the corners of the verandas clay cells for their larvæ are

very numerous in the neighbourhood of Rio. These cells they stuff full of half-dead spiders and caterpillars, which they seem to sting to such a degree as to leave them paralyzed but alive, until their eggs are hatched; and the larvæ feed on the horrid mass of powerless, half-killed victims-a sight which has been described by an enthusiastic naturalist as curious and pleasing!

I was much interested one day by watching a deadly contest between a wasp and a large spider. The wasp made a sudden dash at its prey, and then flew away; the spider was evidently wounded, for, trying to escape, it rolled down a little slope, but had still strength enough to crawl into a thick tuft of grass. The wasp soon returned, and seemed surprised at not immediately finding its victim.

It then commenced as regular a hunt as ever did hound after fox-making short semicircular casts, and all the time rapidly vibrating its wings and antennæ. The spider, though well concealed, was soon discovered; and the wasp, evidently still afraid of its adversary's jaws, after much manoeuvring inflicted. two stings on the under side of its thorax. At last, carefully examining with its antennæ the now motionless spider, it proceeded to drag away the body. But I stopped both tyrant and prey.

Every path in the forest is barricaded with the strong yellow web of a species of spider which was formerly said to make in the West Indies webs so strong as to catch birds. A small and pretty kind of spider, with very long fore legs, lives as a parasite

on almost every one of these webs. I suppose it is too insignificant to be noticed by the great spiders, and is therefore allowed to prey on the minute insects, which, adhering to the lines, would otherwise be wasted. When frightened, this little spider either feigns death by extending its front legs, or suddenly drops from the web.

The web of another large spider, which is generally placed among the great leaves of the common agave, is sometimes strengthened near the centre by a pair, or even four, zigzag ribbons, which connect two adjoining rays. When any large insect, as a grasshopper or wasp, is caught, the spider by a dexterous movement makes it revolve very rapidly, and at the same time emitting a band of threads from its spinners, it soon envelops its prey in a case like the cocoon of a silkworm.

The spider now examines the powerless victim, and gives the fatal bite on the hinder part of its thorax; then, retreating, patiently waits till the poison has taken effect. The virulence of this poison may be judged of from the fact that in half a minute I opened the mesh, and found a large wasp quite lifeless.

It is well known that most of the British spiders, when a large insect is caught in their webs, endeavour to cut the lines and liberate their prey, to save their nets from being entirely spoiled. I once, however, saw in a hothouse in Shropshire a large female wasp caught in the irregular web of a quite small spider, and this spider, instead of cutting the

web, most perseveringly continued to entangle the body, and especially the wings of its prey. The wasp at first aimed in vain repeated thrusts with its sting at its little antagonist. Pitying the wasp, after allowing it to struggle for more than an hour I killed it and put it back into the web.

The spider soon returned; and an hour afterwards I was much surprised to find it with its jaws buried in the orifice through which the sting is protruded by the living wasp. I drove the spider away two or three times, but for the next twenty-four hours I always found it again sucking at the same place. The spider became much distended by the juices of its prey, which was many times larger than itself.

I may here just mention that I found many large black spiders, with ruby - coloured marks on their backs, having gregarious habits. The webs were placed vertically. They were separated from each other by a space of about two feet, but were all attached to certain common lines, which were of great length, and extended to all parts of the community. In this manner the tops of some large bushes were encompassed by the united nets.

I cannot, however, recollect seeing a central nest as large as a hat, in which, Azara says, the eggs are deposited during autumn, when the spiders die. As all the spiders which I saw were of the same size, they must have been of nearly the same age. This gregarious habit among insects which are so bloodthirsty and solitary that even the two sexes attack each other, is a very singular fact.

DARWIN.