INSECT ENEMIES OF LIVE STOCK 173 



the vector of it, Rhipicephalus bursa, it may be of interest 

 to mention that, although in nearly all essential respects 

 the progress of the blood parasite is exactly similar to that 

 observed in bovine piroplasmosis and Margaropus annula- 

 tus, there is one striking difference the larval Margaropus, 

 emerging from eggs laid by an infected mother, can at 

 once transmit red water to another host ; but in the case 

 of Rhipicephalus bursa the larvae do not possess this 

 power, and the adult stage must be reached before disease 

 transmission can be effected. 



MAL DE CADERAS 



The South American Equidce, animals of the horse, mule, 

 and ass tribe, are never attacked by nagana, for the simple 

 reason that the flies transmitting the disease do not occur 

 in the American continent. Another trypanosome disease, 

 known as mal de caderas, is epizootic of asses and mules 

 in South America. The trypanosome causing the disease 

 was discovered in 1901 by Dr Elmassian at Asuncion in 

 Paraguay, and was shortly afterwards named Trypanosoina 

 equinum. Mal de caderas, turnby-baba or tumby-a, as 

 the disease is called in Paraguay and Argentina, or peste 

 de caderas in Brazil, is widely distributed in South America ; 

 presumably imported into the island of Morajo, it spread 

 to the state of Matto Grosso, and at the present time it is 

 known in Brazil, Bolivia, and Paraguay, and in the Argen- 

 tine territories of Chaco, Formosa, and Misiones, and the 

 provinces of Corruntes, Santiago del Estere, and Catamarca. 

 Since 1860 the disease has caused such ravages in Matto 

 Grosso that there are no horses and mules left ; the natives 

 are compelled to use cattle as draught animals, and young 

 bulls are trained for riding purposes ; in whatever region 

 caderas occurs, however, it is most prevalent in marshy 

 districts and after rain. 



Although sheep, goats, dogs, rabbits, guinea pigs, rats, 



