The ants of Blumenau chiefly differ from those described by Belt in that they form very narrow streets, in which they travel only in single file, and also that their nests occur both in the forest and in the open. The commonest species is the _Atta_ (_Acromyrmex_) _discigera_, Mayr, and the workers are never more than 6.5 mm. long. There are other species of _Atta_ which have very similar streets; one, the _Atta hystrix_, Latr., appears to work only at night. A minute description is given of a street of _A. discigera_, which was 26 metres long and about 1.5 cm. wide and high, roofed in in parts wherever possible. It led to a number of small Cupheas, whose leaves the ants were cutting. In the street could be seen a procession of loaded ants going towards the nest, and others empty-handed, going in the opposite direction. Some of the large workers run up and down the road unloaded, and act as road-menders if any accident happens to a part of the track. Other very small workers, which do not cut leaves, may also be seen carried upon the backs or even upon the loads of the actual leaf-cutters. An ant carrying a peculiarly shaped piece of leaf was watched from end to end of the track, and travelled the 26 m. in 70 minutes. The load was twice as heavy as itself. The plants attacked by the ants were found to be very numerous, and the ants seemed to be very capricious in this respect, one day stripping a plant and the next day leaving it untouched. The jaws of the ants are very strong, with serrated edges, and clash together laterally. The ant begins at the edge of a leaf, and cuts out a piece in about five minutes, revolving on one of its hind legs as a centre. When the piece is almost freed, the ant goes on to the main portion of the leaf, cuts through the last piece uniting it with the severed portion, drags up the latter, balances it on edge between its forelegs, and then, grasping it with its jaws, lifts it up above its head, so that the centre of gravity of the load is above the ant itself. It then marches off, down the stem, to the base, over the ground to the end of the street, and along this to the nest, travelling at a very uniform speed, and never letting go its load. The weight thus carried was found, on an average, to be twice that of the ant; but many were found carrying heavier loads, even as much as ten times their own weight!