DISEASES TRANSMITTED BY BLOODSUCKING FLIES 217 



they assume the "salivary trypanosome form" and are then capable of 

 infecting any susceptible animal (Hindle). 



Castellanella rhodesiense (Stephens and Fantham) Chalmers, cause 

 of RHODESIAN SLEEPING SICKNESS of man, is carried by Glossina 

 morsitans Westwood, G. palpalis Robineau-Desvoidy, and G. bretnpalpis 

 Newstead. The insect becomes infective after an incubation period of 

 about 14 days and is infective throughout tlie remainder of its life. The 

 life cycle is not completely worked out, but it is known that the try- 

 panosomes first become established in the intestines and later invade the 

 salivary glands (Hindle). 



Castellanella soudanense (Laveran) Chalmers, cause of TAHAGA of 

 dromedaries in Sudan, EL DEDAB of dromedaries in Algeria, and 

 ZOUSFANA of horses in Sud Oranais, has been experimentally trans- 

 mitted by Stomoxys calcitrant Linnaeus, S. nigra Macquart, Atylotus 

 nemoralis Meigen, and A. tomentosus Macquart. 



.Duttonella caprae (Kleine) Chalmers, cause of an African goat Try- 

 panosomiasis, is transmitted by Glossina hrevipalpis Newstead and G. 

 morsitans Westwood. 



Duttonella cazalbojii (Laveran) Chalmers, cause of SOUMA, an 

 African animal trypanosomiasis, is principally carried by the tsetse flies 

 Glossina palpalis Robineau-Desvoidy, G. longipalpis Wiedemann, G. mor- 

 sitans Westwood, and G. tachinoides Westwood, but may also be trans- 

 mitted by Stomoxys calcitrans Linnaeus, Tahanus higuttatus Wiede- 

 mann, and T. taeniatus Macquart, and possibly Stomoxys nigra Mac- 

 quart. Development of the organism is restricted to the proboscis of 

 the tsetse fly, the flagellates never multiplying in any other part of 

 the alimentary canal. They may change in the proboscis into lep- 

 tomonad or crithidial forms, attach \o the walls of the labrum and under- 

 go rapid multiplication. Under the influence of the salivary secretion 

 some of these fixed flagellates develop into small, actively motile try- 

 panosomes closely resembling the blood forms. This becomes infective 

 from six to ten or more days after ingestion of the parasites. 



Duttonella cazalboui pigritia (Van Saceghem), cause of ZAMBIAN 

 SOUMA of cattle, is carried by Haematopota perturbans according to 

 Van Saceghem who found the organism in the intestinal tract of flies 

 taken on infected animals. 



Duttonella congolense (Broden) Chalmers, cause of GAMBIAN 

 HORSE SICKNESS, is carried by Glossina morsitans and possibly by 

 G. palpalis and species of Glossina, Tabanus and Stomoxys. The various 

 forms of the parasite have been demonstrated in the alimentary canal 

 of G. morsitans 23 days after ingestion. 



Duttonella nanum (Laveran) Chalmers, cause of a fatal BOVINE 

 TRYPANOSO]MIASIS of Africa, is carried by Glossina palpalis, and 



