The subfamily Ceratopogoninae (sensu Wirth, 1965a) is probably a natural (monophyletic) group but includes both blood sucking forms (Culicoidini) and predators on small insects. The insectivorous forms consist of a diversified array of six tribes and many genera represented in moist habitats throughout the world and especially abundant at lake margins.Many predator/prey observations are recorded. The prey consists almost exclusively of the males of other Nematocera or the smaller Ephemeroptera, which the female captures in flight by entering the male (mating) swarms of these insects and hovering until in a position to strike. The initial response is to the swarm-determining landmark, and the female hovers there whether or not potential prey is in flight; groups of hovering females can be induced artificially by suitable markers. These midges themselves form male swarms which the female enters for mating, and the unique method of hunting thus follows a pattern of behaviour already established in relation to another function. The insectivorous tribes have probably been derived from the more plesiomorphic Culicoidini, but the stages in the development of their radically different manner of hunting are not clear.The characteristic form of the mouthparts in the insectivorous genera is described and figured. The prey, after capture in flight, is usually held by the raptorial legs and quickly perforated by the mandibles. A proteolytic saliva is injected and the cellular tissue, except in the longer appendages, is liquefied and sucked out. In most species a single prey individual is not sufficient for one ovarian cycle, and the midge feeds several times. There is some degree of prey specificity, based at least in part on specific responses to the swarm-marker. In several genera there are long tubular "glands" in the abdomen, often everted in flight, whose function is not clearly established. Mobbing of the predator by the intended prey (mosquitoes) is described.The distinctive feature of mating is that the female, in addition to her other prey, often eats the male during mating. Nearly all the records come from the three tribes Heteromyiini, Sphaeromiini, and Palpomyiini. In these tribes (which probably form a relatively apomorphic monophyletic group) the male is usually a dwarf, and the plumose (auditory) antenna is more or less strongly reduced. It is suggested that the female remains in hunting phase when entering her conspecific swarm and captures the male as prey, and that the typical auditory recognition of female by male has become reduced or vestigial. In the more plesiomorphic tribes Ceratopogonini and Stilobezziini the male is normal in size and the antennal plume is fully developed, as in Culicoides, and there are only two records, at most, of the male being eaten during mating.The males eaten during mating are pierced through the head and reduced to an empty cuticle by the action of the lytic saliva. The terminalia however retain their hold, perhaps because of the early destruction of the suboesophageal ganglion, and the dry male cuticle often breaks away leaving the terminalia still attached. The structure of the terminalia and the mating position is described and discussed. Insemination is by spermatophore, which if the male is eaten never leaves the male duct. The terminalia of the male are inverted during mating and in some genera become so permanently early in adult life.An attempt is made throughout to view the phenomena in a phylogenetic context.Numerous illustrations are provided.

The genera Haida Keen and Pseudohaida Hatch are revised and transferred from the tribe Coryphiini to the Anthophagini; the Palearctic genus Eudectus Redten bacher is also placed in the Anthophagini. Eudectus crassicornis LeConte is transferred to the new gents Eudectoides. Two new species are described, Haida bisulcata from the Sierra Nevada in California and H. insulcata from Oregon. Pseudohaida ingrata Hatch is transferred to Subhaida Hatch, a member of the tribe Coryphiini.

The mouthparts and antenna are illustrated for each genus and the male aedeagus for each species. A key is included to aid in the identification of all the included taxa.

A revision of the hydrophilid subfamily Sphaeridiinae (Coleoptera) is presented including a historical review, a discussion of diagnostic characters and techniques, and some conclusive remarks, mostly on the zoogeography of this group in North America.Thirteen genera and 62 species are recognized. Three genera, one subgenus, 12 species, and one subspecies are described as new. Sphaeridiolinus Menozzi, 1921, is placed in synonymy with Sphaeridium Fabricius, 1775; Ercycon Rey, 1885, and Paraliocercyon Ganglbauer, 1904, are placed in synonymy with Cercyon Leach, 1817. On the specific level, Phaenonotum dubium Sharp, 1882, is placed in synonymy with Ph. exstriatum (Say, 1837); Sphaeridium quadrimaculatum Herbst, 1783, marginatum Fabricius, 1787, daltoni Stephens, 1829, semistriatum Laporte, 1840, testaceum Heer, 1841, humerale Westhoff, 1881, nigrum Csiki, 1953, and pulchrum Csiki, 1953, with S. bipustulatum Fabricius, 1781; Sphaeridium striolatum Heer, 1841, pictum Ménétries, 1832, marginatum Normand, 1933, nigerrimum Reitter, 1909, inhumerale Csiki, 1953, and confluens EndrÖdy-Younga, 1967, with S. scarabaeoides (Linné, 1758); Cercyon testaceus Blatchley, 1923, with C. praetextatus (Say, 1825); Cercyon fulvipennis Mannerheim, 1852, with C. limbatus Mannerheim, 1843; Cercyon mulsanti Ganglbauer, 1904, with C. quisquilius (Linné, 1761); Cercyon impunctatus Kuwert, 1890, and janssoni Nyholm, 1952, with C. unipunctatus (Linné, 1758); Cercyon incrematus Notman, 1920, with C. lateralis (Marsham, 1802); Cercyon erythropterus Mulsant, 1840, discoidalis J. Sahlberg, 1913, basillaris Notman, 1920, and bifenestratellus EndrÖdy-Younga, 1967, with C. haemorrhoidalis (Fabricius, 1775); Cercyon rufipennis Csiki, 1953, with C. impressus (Sturm, 1807); Cercyon rubripennis Kuwert, 1890, with C. melanocephalus (Linné, 1758); Cercyon separandus Rey, 1885, and pictithorax Gridelli, 1926, with C. terminants (Marsham, 1802); Cercyon binotatus Stephens, 1829, and ruficollis Schilsky, 1888, with C. litoralis (Gyllenhal, 1808); Cercyon falli Winters, 1944 (nomen nudum), with C. analis (Paykull, 1798); Cybocephalus unicolor Motschulsky, 1845, with Cercyon adumbratus Mannerheim, 1843; Cryptopleurum cerei Schwarz, 1899, with C. impressum Sharp, 1882.Neotypes are designated for Cercyon praetextatus (Say), C. occallatus (Say), and C. minusculus Melsh. Lectotypes are designated for Dactylosternum advectum Horn, D. cacti (LeC.), Oosternum costatum Sharp, Cercyon roseni Knisch, C. opacellus Fall, C. pubescens LeC., C. kulzeri Knisch, C. nevadanus Knisch, C. floridanus Horn, C. testaceus Blatch., C. limbatus Mannh., C. fulvipennis Mannh., C. variegatus Sharp, C. indistinctus Horn, C. adumbratus Mannh., C. fimbriatus Mannh., C. luniger Mannh., C. maculatus Melsh., Genyon navicularis (Zimm.), Megasternum posticatum Mannh., Cryptopleurum impressum Sharp, C. cerei Schw., and C. subtile Sharp.Keys to tribes, genera, and species are provided. The tribes and genera are described; each species is described and illustrated, and all available bionomic and distributional data are presented; distributional records are mapped.

The tribe Coryphiini Hatch is redefined to include six genera and 18 species from North America. Two new genera are described: Gnathoryphium (type-species G. mandibulare n. sp.) and Holoboreaphilus (type-species Boreaphilus nordenskioeldi Maklin). Seven new species are described: Coryphium nigrum from the northeastern United States and Subhaida californica, S. aptera, S. monticola, S. utahensis, S. sinuata, and Gnathoryphium mandibulare from western North America. The genus Occiephelinus Hatch from western North America and Planeboreaphilus Shibata from Japan are considered junior synonyms of Coryphium Stephens. The western North American species formerly placed in Ephelinus Cockerell are transferred to the genus Coryphium. Pseudohaida ingrata Hatch is transferred to the genus Subhaida Hatch. Boreaphilus americanus Notman is placed in synonymy with B. henningianus C.R. Sahlberg.All genera and species are described. Habitus drawings, and line drawings of the antenna, labrum, maxilla, mandible, mentum, and labium are presented for at least one species of each genus. The aedeagus is illustrated for all the species except two that are known only from females.Of the species treated, three are Holarctic in distribution, four are restricted to eastern North America, and 11 are endemic to the mountainous areas of western North America.All available biological information for each species is included and a key is presented to aid in the identification of all the genera and species of the tribe in North America.