Bees and wasps of a countless number of species abound in every region of the continent. Some build their habitations, composed of a papery substance, attached to the under side of the broad leaves of the tucuma and other palms. Others, again, form them in hollow trees, or among their roots in the earth. Many build in houses, or pierce their mud walls till they look as if riddled with shot. Others make holes in the ground, especially in sandy places. Others, again, construct their habitations of clay, and fasten them to the boughs of trees or to buildings. There are, indeed, mason bees, carpenter bees, and miner bees and wasps. Watch the little, pale green bombex, or sand-wasp, at work, throwing out with its fore-feet jets of sand from the hole it is forming in the sloping bank. In a wonderfully short time the female miner has formed a gallery two or three inches in length. Out she backs, making a few turns round the entrance to admire her work--or, probably, to take note of the locality--and then away she flies. She may be absent for a few minutes, or perhaps for an hour, according to her success in hunting. At length back she comes with a big fly in her grasp, benumbed by her sting. She carries it in, lays an egg in the body, which will serve as food for the soft footless grub soon to be hatched, and then closing the entrance, sets to work to form a new nursery like the first, which she will furnish in the same careful manner. It is curious how she can find her way back, for often she has to go half a mile before she can find a fly to suit her purpose. Another species,--the Monedula signata,--as large as a hornet, is particularly useful in carrying off the teasing flies, the bloodthirsty motucas, which buzz round the voyager on the Amazon when at anchor near a sand-bank. Bates was rather startled by seeing one fly directly at his face, on which it had espied a motuca, and which it carried off, holding it tightly to its breast. The pelopaeus wasp builds a nest of clay, shaped like a pouch, two inches in length, and attaches it to a branch. It forms the clay in little round pellets, kneading it with its mandibles into a convenient shape, and humming cheerfully while engaged in its work. On arriving with the ball of moist clay it lays it on the edge of the cell, and then spreads it out round the circular rim by means of the lower lip, guided by the mandibles--sitting astride while at work. On finishing each addition it takes a turn round, patting the sides with its feet inside and out, before flying off for a fresh pellet. It feeds on small spiders, which it reduces to a half dead state by its sting, thus to serve as food for its progeny. One bee,--the Trypoxylon aurifrons,--builds a nest of clay like a squat round bottle or carafe; generally in rows, one beside the other, on a branch, or in the corners of a building.