The transformations of the mites are interesting to the philosophic zoologist, since the young of certain forms are remarkably different from the adults, and in reaching the perfect state the mite passes through a metamorphosis more striking than that of many insects. The young on leaving the egg have six legs, as we have seen in the case of the Ixodes. Sometimes, however, as, for example, in the larva, as we may call it, of a European mite, Typhlodromus pyri, the adult of which, according to A. Scheuten, is allied to Acarus, and lives under the epidermis of the leaves of the pear in Europe (while Mr. T. Taylor, of the Department of Agriculture at Washington, has found a species in the pear leaves about Washington, and still another form in peach leaves), there are but two pairs of legs present, and the body is long, cylindrical and in a degree worm-like. I have had the good fortune to observe the different stages of a bird mite, intermediate in its form between the Acarus and Sarcoptes, or Itch mite. On March 6th, Mr. C. Cooke called my attention to certain little mites which were situated on the narrow groove between the main stem of the barb and the outer edge of the barbules of the feathers of the Downy Woodpecker, and subsequently we found the other forms in the down under the feathers. These long worm-like mites were evidently the young of a singular Sarcoptes-like mite, as they were found on the same specimen of Woodpecker at about the same date, and it is known that the growth of mites is rapid, the metamorphoses, judging by the information which we now possess, occupying usually but a few days. [Illustration: 143. Egg-eating Mite.]