Contents -- Preface -- The Biological Role of Mayflies -- Methods -- Collecting Nymphs -- Collecting Adults -- Rearing -- Preservation of Specimens -- Labeling of Specimens -- Preparation of Slides -- Systematics -- Classification System -- Use of the Keys -- Morphology of Key Characters and Terminology -- Distribution -- Key to Nymphs -- Key to Adults -- The Families of Mayflies -- Nymphal Characteristics -- Nymphal Habitats -- Nymphal Habits -- Life History -- Adult Characteristics -- Mating Flights -- Taxonomy -- Distribution -- Family SIPHLONURIDAE -- Subfamily Siphlonurinae -- Subfamily Acanthametropodinae -- Subfamily Isonychiinae -- Family METRETOPODIDAE -- Family SIPHLAENIGMATIDAE -- Family AMETROPODIDAE -- Family BAETIDAE -- Family OLIGONEURIIDAE -- Subfamily Oligoneuriinae -- Family HEPTAGENIIDAE -- Subfamily Heptageniinae -- Subfamily Arthropleinae -- Subfamily Pseudironinae -- Subfamily Anepeorinae -- Subfamily Spinadinae -- Family LEPTOPHLEBIIDAE -- Family EPHEMERELLIDAE -- Subfamily Ephemerellinae -- Family TRICORYTHIDAE -- Subfamily Leptohyphinae -- Family NEOEPHEMERIDAE -- Family CAENIDAE -- Family BAETISCIDAE -- Family PROSOPISTOMATIDAE -- Family BEHNINGIIDAE -- Family POTAMANTHIDAE -- Family EUTHYPLOCIIDAE -- Family EPHEMERIDAE -- Subfamily Ephemerinae -- Subfamily Pentageniinae -- Family PALINGENIIDAE -- Family POLYMITARCYIDAE -- Subfamily Polymitarcyinae -- Subfamily Campsurinae -- Appendix I. A Guide to Changes in Scientific Names -- Appendix II. Suppliers of Collecting and Rearing Equipment -- Bibliography -- Index -- A -- B -- C -- D -- E -- F -- H -- I -- J -- K -- L -- M -- N -- O -- P -- R -- S -- T -- U -- W.