Volume 1 covers 42 of the 106 families of flies (sometimes termed the Lower Diptera) and also 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. While volume 1 includes several introductory chapters and treats 42 families of flies in the Lower Diptera, volume 2 covers the remaining 64 families of flies that make up the Higher Diptera (or Cyclorrhapha). These include families of house flies, fruit flies, bot flies, flower flies and many other lesser-known groups. The text is accompanies by over 1660 line drawings and photographs.