The Trypanosomatid Parasites of Horseflies with the Description of Crithidia rileyi n. sp.*

Abstract

SYNOPSIS. A new species, Crithidia rileyi (Trypanosomatidae), is described from Tabanus epistates. The most characteristic feature of the flagellate is the frequent occurrence of a broad sucker‐like posterior end. In contrast to other species of Crithidia it multiplied very slowly in the first few weeks after isolation. A review of the literature shows that trypanosomatids of two generic types, Crithidia and Blastocrithidia, have been described from flies of the family Tabanidae, although they have nearly always been regarded as stages of the same organism. Some or all of those of the Blastocrithidia type are stages of Trypanosoma theileri. The Crithidia are probably not stages in the development of any trypanosome.

Transmission of Megatrypanum Trypanosomes to Cervus dama by Tabanidae1

“…Kraneveld (1 2) was able to infect one calf and four water buffaloes by using excessive numbers of tabanids. These results were considered inconclusive by some authors (see 13, 19,20). For example, the initial negative status of the cattle used for Noller's (1 7) transmission studies was doubted.…”

The nature of trypanosomatid infections of Tabanidae in central New York State

“…Patton decided that a true Crithidia had incorrectly been named Herpetomonas. Using this very unconventional approach to taxo¬ nomic principles, Patton implied that a true Crithidia was * Recently, Wallace (1962) assigned the "formes monadiennes" of Herpetomonas subulata Leger 1904 to their appropriate taxonomic position as Blastocnthidia subulata (Leger, 1904 ) Wallace, 1962 . In addition, Wallace (1962), following the original description of Crithidia Leger, 1902, grouped the "formes gregariniennes" in their rightful position as Crithidia spp.…”

“…Many of the parasites were attached to the gut wall. Wallace (1962) stated, "In size, shape, location and in being attached to the gut wall the flagellates Noller described in the insect (T. glaucopis) would now be identified as Crithidia." However, the hind position of the kinetoplast is not consistent with the generic description of Crithidia.…”

“…In addition, as mentioned earlier, Noller cultured washings from the infected hindgut in blood (goat) agar bouillon at room temperature and, in three days, observed typical cattle trypanosomes identical to culture forms of T. theileri (i.e., epimastigote forms). Wallace (1962) accepted the fact that Noller's cultured organisms were Bias tocrithidia or Trypanosoma. He tried to reconcile the apparent discrepancy between the insect forms and the culture forms by introducing the possibility that the fly Noller cultured had a mixed infection.…”

“…Tabanidae as Hosts and Vectors of Trypanosomatidae Wallace (1962Wallace ( , 1966, in reviewing the described trypanosomatid parasites of tabanids, grouped most of the parasites into two generic types, Crithidia Leger, 1902 andBlastocrithidia Laird, 1959. various other insect families (e.g., Patton, 1910, Wallace, 1943, Wallace and Clark, 1959 for additional references, see Wallace, 1966) (McGhee, 1968;Hoare, 1972).…”