under a spring catch." Later, when examined, the butterfly was found to possess a drum, the organ being found, according to Mr. Doubleday, at the base of the fore wings, between the costal nervure and the sub-costal. With the beetles Darwin was disappointed: there were not so many large and attractive forms as he had expected, though small ones existed in vast numbers, and we find him expressing surprise at the absence of carnivorous beetles when the hot tropical country is the home of the carnivora or flesh-eaters among larger animals. Bees and wasps were so abundant that the thought was suggested that perhaps they supplied the place of carnivorous insects.

Many hours were spent in watching the ant armies traversing the wood, and experimenting to test their intelligence and bravery. The habits of the wasp were a constant source of pleasure to him. In the corner of a veranda a certain species had made celllike homes of clay; these they stuffed full of insects of various kinds, which had been paralysed by the sting of the wasp, and while helpless the eggs of the latter were deposited in them, where they ultimately hatched out, the grub obtaining its food from the comatose victim.

The habits of the larger wasps were also closely studied, and the bull-dog- or bloodhound-like tenacity of the creatures, now so familiar, observed carefully for the first time.

Darwin noticed that the number of spiders here was greater, in proportion to other insects, than in England. The jumping spiders particularly inter

Examination of the Spider.

39

ested him; their leaps upon their prey reminding him of the tiger in pursuit of its victim. Over every pathway in the forest he found a strong elastic yellow web of a spider, allied to the Epeira clavipes, and note how carefully he examined them! In every web was found a small parasitic form, which lived here undisturbed by its giant ally, feeding upon the minute insects entrapped,-the crumbs from the big spider's table. The young naturalist here observed a remarkable instance of defence on the part of a spider. As he approached, the little insect imparted to its web a swinging movement, which increased so rapidly that in a few moments the cunning insect was invisible, or nearly so, from the rapidity of its motions. This spider had a most skilful method of disposing of its victims. The moment a wasp or fly became entangled, the Epeira held it at arm's length, and, in some miraculous way, whirled it over and over, winding it up in a broad band of threads, taken from its spinners, so that in a few moments the captive appeared to be encased in a cocoon, and then helpless was killed by the deadly jaws of the monster.

To show the virulence of the poison, Darwin found that half a minute was sufficient to kill a large wasp.

On July 5, 1832, the Beagle left Rio, sailing for the Plata. In the mouth of the latter he studied the porpoise, watching its movements across the bow as the vessel rushed along at full speed. Seals and penguins were present in great numbers, and were so demonstrative at night that the officer of

the deck thought the noises proceeded from the shore.

The Plata is somewhat noted for its electrical displays, and the young naturalist was witness to some remarkable phenomena. The tip of the masts and ends of the booms became illuminated with balls of fire, while the vane upon the topmast looked as though it had been rubbed with phosphorus. The ocean itself seemed to vie with the atmosphere here in its phosphorescent displays, and gleamed with lights so brilliant that Darwin could trace everywhere the movements of seals and penguins, and even distinguish the forms as they were outlined by the mysterious phosphorescent light. Accompanying these displays was an electrical storm, which caused vivid flashes of lightning to play about the ship.

The Beagle had now reached the first point of her projected work, which was to survey the coast of South America from the Plata south, an undertaking which it was estimated would take two years to accomplish.

Darwin went ashore, and made his headquarters at Maldonado, a rich collecting district from a zoölogical standpoint. Collecting had its drawbacks here, as, a few days previous, a man had been found murdered, hard by a cross which formed the record of a similar crime. A guard, then, seemed necessary, and perhaps no naturalist ever went forth after bugs, birds, and reptiles with so singular an escort. To see the cavalcade approaching, one might well have supposed that men, not simple specimens, were the object. The troop consisted of a dozen or more