Preliminary report of microsporidia in Simuliidae larvae from Argentina.

Amblyospora bracteata, Polydispyrenia simulii, and 3 other undescribed microsporidia are reported from 11 species of neotropical blackfly larvae collected from streams in Buenos Aires (eastern) and Neuquen (southwestern) provinces of Argentina. Preliminary light and electron microscopy studies indicate that 2 of the undescribed species belong in the family Thelohaniidae and the third species is placed in the family Caudosporidae. Ten species of Argentine blackflies are recorded as new host records for A. bracteata and P. simulii.

Development of Edhazardia aedis (Kudo, 1930) n. g., n. comb. (Microsporida: Amblyosporidae) in the mosquito Aedes aegypti (L.) (Diptera: Culicidae).

A microsporidium of the mosquito Aedes aegypti (L.), identified as Nosema aedis Kudo, 1930, was found to be a heterosporous species with 3 sporulation sequences. Usually, 1 sequence developed in a parental generation host individual that was infected per os as a larva and the other 2 developed concurrently in a filial host larva that was infected transovarially. Under some conditions there were deviations from the parental host-filial host alternation. The 1st sporulation sequence was diplokaryotic (diploid in a particular sense) throughout; the other 2 arose from diplokaryotic meronts, developed concurrently and ended with haploid spores. Haplosis in 1 case was by means of dissociation of the diplokaryon. In the other case it was by meiosis. Conflicting reports about whether the members of the diplokaryon in the latter sequence separate and undergo meiosis individually or coalesce and undergo meiosis as 1 nucleus were resolved in favor of the latter idea. A new genus in family Amblyosporidae was created to contain this species, which then became Edhazardia aedis (Kudo, 1930) n. g., n. comb.

Fine structure and development of Pilosporella chapmani (Microspora: Thelohaniidae) in the mosquito, Aedes triseriatus (Say).

New information on the life cycle and fine structure of Pilosporella chapmani, a microsporidium of the mosquito Aedes triseriatus, is presented. Pilosporella chapmani is shown to have two sporulation sequences, one of them being involved in transovarial transmission. One sequence, involving meiosis and production of a moniliform sporogonial plasmodium, occurs in the larval fat body, resulting in eight uninucleate, spherical, and fully developed spores. The other occurs in oenocytes of adult mosquitoes and results in isolated, binucleate, elongate, and thin-walled spores. Also, for the first time, metabolic products are shown to be expelled into the surrounding host tissues through the wall of the sporocyst.

Rickettsia-like organism causing disease in a crangonid amphipod from Florida.

A rickettsia-like organism causing high mortality and gross pathology has been found infecting over 40% of a population of the freshwater crustacean, Crangonyx (near) floridanus Bousfield, in Florida. This is the first report of a rickettsia-like organism from a strictly aquatic animal. Morphological and developmental stages of the organisms range in size and shape from small, dense bacilliform cells measuring 150 nm in diameter by 395 nm in length, to large sausage-shaped cells 0.5 by 3 mum.