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in ANIMAL LIFE IN THE TROPICAL FORESTS 279found, and other tropical countries are no doubt equally rich.I will first give some account of the various species observedin the Malay islands, and afterwards describe some of themore interesting South American groups, which have beenso carefully observed by Mr. Bates on the Amazons and byMr. Belt in Nicaragua.Among the very commonest ants in all parts of the worldare the species of the family Formicidse, which do not sting,and are most of them quite harmless. Some make delicatepapery nests, others live under stones or among grass.Several of them accompany Aphides to feed upon the sweetsecretions from their bodies. They vary in size from thelarge Formica gigas, more than an inch long, to minutespecies so small as to be hardly visible. Those of the genusPolyrachis, which are plentiful in all Eastern forests, areremarkable for the extraordinary hooks and spines with whichtheir bodies are armed, and they are also in many casesbeautifully sculptured or furrowed. They are not numerousindividually, and are almost all arboreal, crawling about barkand foliage. One species has processes on its back just likefish-hooks, others are armed with long, straight spines. Theygenerally form papery nests on leaves, and when disturbedthey rush out and strike their bodies against the nest so as toproduce a loud rattling noise but the nest of j every speciesdiffers from those of all others either in size, shape, or position.As they all live in rather small communities in exposedsituations, are not very active, and are rather large and conspicuous,they must be very much exposed to the attacks ofinsectivorous birds and other creatures, and having no stingor powerful jaws with which to defend themselves, they wouldbe liable to extermination without some special protection.This protection they no doubt obtain by their hard smoothbodies, and by the curious hooks, spines, points, and bristleswith which they are armed, which must render them unpalatablemorsels, very liable to stick in the jaws or throats of theircaptors.A curious and very common species in the Malay islandsis the green ant ((Ecophylla smaragdina), a rather large, longlegged,active, and intelligent-looking creature, which lives inlarge nests formed by gluing together the edges of leaves,