PROCESSIONARY CATERPILLARS.
In the month of February, these ‘processionary caterpillars’—as they have come to be called—are seen in large numbers both at Arcachon and Biarritz. Sometimes chains of two and three hundred may be observed marching in solemn procession either on the plage or on the roads. It is clearly seen that they choose the smooth paths of life, as they are rarely, if ever, seen to perambulate the sandy, uneven forest, from which they emerge throughout the whole day. Not unfrequently, they mount the steps of a villa, to take a peep at the interior, to the dismay of invalids unaccustomed to such extraordinary, though perfectly harmless callers. On such occasions, they divide into small detachments, as if conscious that the presence of a whole battalion might prove inconvenient; for at other times, whatever be the length of the chain, or how oft soever divided, they invariably unite, and the one who starts as leader retains the post, as if by common consent, until their return to the nests they have left in the early morning. Alas! for the fruit-trees that fall in their way on what may be termed their foraging expeditions. They halt many times to regale themselves on succulent leaves, and when fully satisfied, return to their nests in the evening. These nests are longitudinal in form, similar to those of wasps, but smaller. They are composed of the dry needle-points of the pine, divided into minute particles; and are ingeniously woven together by gossamer threads as fine as those of the spider, but in appearance so silky as to resemble the work of the silkworm. As it covers the whole nest, the intention is evidently to keep the fabric together. Should any one, impelled by curiosity, attempt to pull the nest to pieces, to discover more of this texture, and afterwards touch his own eyes, inflammation may set in, and even death ensue. This enables us to understand how injurious so virulent a poison must be to the young trees. Many of large growth in the forest of Arcachon have been completely destroyed by these insects. They are never seen during the great heat of summer. In mid-winter, they leave the nests by shoals, unite, and burrow in the earth. There, underground, the long chain forms itself into a ball, and many of the caterpillars die. After a time, the rest emerge from their cocoon existence, and return to the trees, where they make fresh nests on the deserted ones of the preceding year.