Classificação de Phaonia Robineau-Desvoidy (Diptera, Muscidae) da região neotropical: I. Considerações sobre a sinonímia de Bigotomyia Malloch, com descrição de uma espécie nova

Some considerations about the synonym of Bigotomyia Malloch, 1922 and Phaonia R.-D, 1830 are made. A new species, P. hugonis sp. n. is described from Peru and Equador.

New synonymy and new species in neotropical chloropidae (Diptera)

An ephydrid, Hyadina porteri Brèthes, 1919, is found to be a senior synonym of Hippelates australis Sabrosky, 1955. New combination: Liohippelates porteri (Brèthes). Two new species, Pseudogaurax souzalopesi from Peru and P. silbergliedi from Panama are described and placed in the synopsis by Sabrosky (1966).

The neotropical genus Opeatocerata Melander (Díptera, Empididae)

The Neotropical empidid genus Opeatocerata Melander, hitherto known from only a sigle female from Mexico, is redefined in the light of new material, including males. Three new species are described and illustrated, a key provided and the presence of the genus now additionally established in Costa Rica, Panama, Bolivia, Ecuador, Trinidad and Brazil.

The neotropical biting midges related to Culicoides paraensis (Diptera: Ceratopogonidae)

Culicoides paraensis (Goeldi), a common and widespread American bloodsucking midge that has been incriminated in the transmission of Mansonellosis and Oropouche Fever of humans in South America, is redescribed and figured. All published records are listed and new distribution is based on examination of extensive collections from throughout its range. Three closely related species of the subgenus Haematomyidium that have been confused with C. paraensis are briefly redescribed and figured, and a key is presented for their identification.

Two new neotropical species of predaceous midges of the tribe sphaeromiini (Diptera: ceratopogonidae)

Two new Neotropical species of the tribe Sphaeromiini are described and illustrated, Mallochohelea limitrofe from Argentina and Uruguay, and Neobezzia wirthi from Argentina. The first species is only known from the female sex, being the second one described from both, female and male specimens.

Sphaerohelea, a new neotropical predaceous nidge genus of the tribe Sphaeromiini (Diptera: ceratopogonidae)

Sphaerohelea, a new Neotropical genus of predaceous midges related to Lanehelea, Spnaeromias, Chelohelea, Phaenobezzia and Leehelea is described and illustrated and ilustrated from female specimens. This new genus includes only one species, Sphaerohelea biestroi n. sp. from northeastern Argentina as a type-species.

Life history studies of heterophyid Trematodes in the neotropical region: Ascocotyle (Leighia) hadra sp.n

The life cycle of Ascocotyle (Leighia) hadra n.sp. was experimentally reproduced, starting from cercariae from naturally infected Littoridina parchappei, collected from Los Ranchos stream, near Mercedes city, Buenos Aires Province, Argentina. Metacercariae were found encysted in the liver and mesentery of experimentally and naturally infected fishes Cnesterodon decemmaculatus and Jenynsia lineata. Adults were obtained experimentally in chicks and mice. The natural host is unknown. The new species is compared with Ascocotyle (Leighia) mcintoshi Price 1936 as described by Leigh, 1974, differing in behavior and morphology of cercarial, metacercarial and adult stages

Downeshelea bicornis, a new neotropical predaceous midge from Brazil (Diptera: Ceratopogonidae)

A new Brazilian species of Downeshelea Wirth & Grogan, D. bicornis, is described and illustrated from a male specimen

Two new neotropical species of Monohelea Kieffer and Downeshelea Wirth & Grogan (Diptera: Ceratipogonidae)

Two new Neotropical predaceous midges are described and illustrated, Downeshelea charrua from Uruguay, and Monohelea bidenata from Argentina. The first species is described from female and male specimens; only one male is know from the second.

Life history of Pygidiopsis crassus n. sp. (Trematoda, Digenea, Heterophyidae) in the neotropical region

The life cycle of Pygidiopsis crassus n. sp. was experimentally reproduced, starting from cercariae from naturally infected Littoridina parchappei collected from Lujan River and different ponds in Buenos Aires Province, Argentina. Metacercariae were found encysted in the body cavity of experimentally and naturally infected fishes Cnesterodon decemmaculatus and naturally infected Jenynsia lineata. Adults were obtained experimentally in chicks and mice. The natural host is unknown. The new species is compared with Pygidiopsis macrostomum Travassos 1928, from Rattus norvegicus and from Noctilio leporinus mastivus, differing in body and egg sizes, in the size relation of oral and ventral sucker and the shape of excretory vesicle.

Hysterothylacium rhamdiae sp.n., (Ascaridoidea: Anisakidae) from a Neotropical Catfish, Rhmdia sapo (Pisces: Pimelodidae)

A new species of Hysterothylacium is described and figured. The nematodes were collected from the intestine of a neotropical catfish, Rhamdia sapo, collected from its southernmost locality (Napostá stream and Sauce Grande river, Buenos Aires Province). The specimens resemble H. murrayense but differ in having a shorter spicules, in the number and distribution of papillae and the relative size of intestinal caecum ventricular appendix.

A new neotropical predaceous midge, Downeshelea deanei, and redescription of Downeshelea guianae (Wirth)(Diptera: Ceratopogonidae)

A new species of Downeshelea Wirth & Grogan, D. deanei Felippe-Bauer & Quintelas, is described and illustrated from a male specimen from Trinidad, and a redescription of D. guianae (Wirth) is given.

Neotropical Monogenoidea. 23. Two new species of Gyrodactylus (Gyrodactylidae) from a Cichlid and an Erythrinid fish of Southeastern Brazil

Two new species of Gyrodactylus Nordmann, 1832 (Platyhelminthes, Monogenoidea) are described from fishes collected from southeastern Brazil. Gyrodactylus geophagensis n. sp. was collected from the body surface of the "cará", Geophagus brasiliensis (Quoy and Gaimard, 1824) (Cichlidae), from the Rio da Guarda, state of Rio de Janeiro; its major diagnostic features are the morphology of the anchor with a short, truncate superficial root and the shape of the hooks - with a long, delicate shaft. Gyrodactylus trairae n. sp. parasitizes the body surface of the "traíra", Hoplias aff. malabaricus (Bloch, 1794) (Erythrinidae), from the rio Guandu, state of Rio de Janeiro and can be easily differentiated from other species of the genus by having a thin, dorsal bridge, connecting the superficial bar with the spathulated shield. These are the first species of Gyrodactylus formally reported from Brazil. Presently, 26 species of Gyrodactylidae are known from freshwater fishes in the neotropical region; a list of these species is provided.

Neotropical Monogenoidea. 24. Rhinoxenus bulbovaginatus n. sp. (Dactylogyridae, Ancyrocephalinae) from the nasal cavity of Salminus maxillosus (Osteichthyes, Characidae) from the Rio Paraná, Paraná, Brazil

Rhinoxenus bulbovaginatus n. sp. is described from the nose of Salminus maxillosus (Characidae) collected in the basin of the rio Paraná, near the city of Porto Rico, state of Paraná, Brazil. The new species can be differentiated from the other three species in the genus by the morphology of the copulatory complex, vagina, and ventral anchor. The sister group relationship of the known species of Rhinoxenus was determined using techniques of Phylogenetic Systematics (Cladism). The resulting cladogram (C.I.=100%) indicates that the new species is most closely related to R. piranhus Kritsky, Boeger and Thatcher, 1988. The other two species of the genus, R. arietinus Kritsky, Boeger and Thatcher, 1988 and R. nyttus Kritsky, Boeger and Thatcher, 1988, both parasites of Anostomidae fishes, have a paraphyletic position in the cladogram, suggesting that the origin of at least one of them can not be associated to cospeciation.