True flies, or Diptera, are an exceedingly diverse and tremendously important group of animals not only because of their impact on human health, but also because of their varied roles as decomposers, herbivores, predators and parasites of other animals. This two-volume book, a collaboration of over 70 experts on Diptera, is the first-ever resource for the identification and understanding of Central American flies. Together, the two volumes treat all 106 families of flies found in the region, including discussions of biology, economic importance, classification, identification to the genus level as well as a synopsis of each genus. In a time of major ecosystem destruction, this work provides the basis for understanding the biodiversity of one of the major orders of insects in a large tropical region. It will be the foundation for future taxonomic studies for decades to come. Volume 1 covers 42 of the 106 families of flies - sometimes termed the Lower Diptera - and includes introductory chapters dealing with morphology and terminology, natural history, economic importance and phylogeny of Diptera as well as keys to all the Central American fly families for both the adult and larval stages. The text is accompanied by over 1500 line drawings and 144 color photographs of flies.