in Natural History, a name given by the common people of America to a tree, the leaves of which, at a certain time of the year, are said to produce flies. On examining these leaves about the middle of summer there are found on them a sort of bags of a tough matter, of about the size of a filbert, and of a dusky greenish colour. On opening one of these bags with a knife, there is usually found a single full-grown fly, of the gnat kind, and a number of small worms, which in a day or two more have wings, and fly away in the form of their parent. The tree is of the mulberry kind, and its leaves are for the most part largely stocked with these insect bags; but they are generally found to contain the insects in their worm state; and when these become winged, they soon make their way out. The bags begin to appear when the leaves are young, and afterwards grow with them; but they never rumple the leaf or injure its shape. They are of the kind of leaf-galls, and partake in all respects, except size, of a species which is frequent on the large maple, or, as it is called, the sycamore.