Excerpt from Manual of North American Diptera The order of two-winged insects known as flies or Dip tera includes more than forty thousand known species from different regions of the world. Since many of the species are small, or even minute, and inconspicuous, and since the order as a whole has not received the at tention from collectors and students of entomology that other and more attractive groups have, it is very certain that many more await discovery. A very reasonable es timate would place the entire number of species of flies at present in existence at more than eighty thousand. From North America the recent catalogue of Aldrich gives a list of about eight thousand species, distributed in more than a thousand genera. The subject is a wide one and replete with interest. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.