Insecta, a class of arthropods, is the largest group of animals known (includes wasps, bees, and ants), whose members have three pairs of jointed legs and are characteristically divided into three anatomical portions. Presented in twenty extensively illustrated volumes, Microscopic Anatomy of Invertebrates provides specific and exhaustive coverage of all the major invertebrate phyla, offering full accounts of their gross, histological, and ultrastructural anatomy. The twenty individual volumes are arranged phylogenetically, beginning with the protozoa, defined herein as the motile protists, and concluding with the invertebrate members of the phylum Chordata.