To reach the exploitation field where they find food, many ants follow visible and well-traced routes which radiate around their nest. .These routes are commonly rather broad near the orifice, sometimes several centimeters in breadth, but they become -progressively narrower, sometimes branching, then ending in uncharted ground where the ants act as explorers. The Messors, most of our.species of Lasius, Formica pratensis, and Formica rufa, the Tapinomas, the Pheidoles, etc., make routes of this sort. The species of Cataglyphis, on the contrary, travel individually. Aside from these permanent roads which may be abandoned after exploration, ants often follow temporary roads which are made in great number during a limited period. It is almost always when they are moving the colony that the ants which have permanent roads establish temporary roads, but this is also done when exploration is in view, as has been noticed with Atta in tropical America, which climbs trees to cut bits of leaves destined for its fungus gardens. Several species in our country make only temporary roads. The sanguinary Formica and its near relative, the ash-colored Formica, make very few others, and only at the time when they are moving the colony. Roads of this sort are followed by the Amazon ant when it is going to neighboring nests of Formicas to capture the brood which will give it slaves. Each expedition comprises a whole phalanx of workers, and the path remains until the pillage is completed.