498 FAMILY: TRYPANOSOMID^ 



remark applies to T. triatomce, described by Kofoid and McCiilloch (1916) 

 from the bug, Triatoma jprotracta, which lives in the nest of the wood rat, 

 Neotoma fuscipes, of California. Hefpetomonas rangeli Tejera, 1920, 

 horn. Rhodnius prolixus, and Crithidia vacuolata Rodhain, Pons, Vanden- 

 branden, and BequaBrt, 1913, from Rhinocoris albopilosus, may also 

 represent the invertebrate phases of trypanosomes. 



III. NON-PATHOGENIC TRYPANOSOMES TRANSMITTED BY SPECIES OF 

 TABANUS, MELOPHAGUS, OR OTHER BLOOD-SUCKING ARTHROPODA. 



Trypanosomes of Cattle. 



Trypanosoma theileri Laveran, 1902. — Synonyms: T. transvaaliense 

 Laveran, 1902; T. lingardi Blanchard, 1904; T. Mmalayanum Lingard, 1906; 

 T. indicum Lingard, 1907; T. muktesari Lingard, 1907; Trypanozoon theileri Liilie, 

 1906; Trypanosoma wriiUewsMi Wladimirofl and Yakimoff, 1908; T. americanum 

 Crawley, 1909; T. frcmJcFiosch, 1909; T. falshawi Kmith, 1909; T.sclieini Knuth, 

 1909; T. rutherfordi Hadwen, 1912; T. schonebecM Mayer, 1913. 



Theiler (1903) described a large trypanosome which he had found in 

 cattle in South Africa. He had sent blood-films to Laveran, who (1902a) 

 named it T. theileri. Since that date similar forms have been discovered 

 in various parts of the world, and have received different names. Lingard 

 (1903-1907) described three species from Indian cattle — T. himalayanum, 

 T. indicum, and T. fnuktesari. Frosch (1909) described as T. franJc a 

 trypanosome of cattle in Germany, while Knuth (1909) recorded T . falshawi 

 and T. scheini from Singapore and Annam. Watson and Hadwen (1912) 

 saw a similar form, named T. rutherfordi, in Canada. Crawley (1909) 

 gave the name T. americanum to a trypanosome of American cattle. 

 A large form was described from the Lithuanian bison by Wrublewski 

 (1908), and named T. wrublewskii by Wladimiroff and Yakimoff (1908). 

 The last observer (1915) came to the conclusion that the trypanosome 

 was in reality T. theileri. T. transvaaliense was described by Laveran 

 (1902a) from blood-films from South African cattle sent him by Theiler. 

 He regarded it as a distinct species, because the kinetoplast was midway 

 between the nucleus and posterior end of the body instead of being near 

 the posterior end. For the same reason Croveri (1920) suggested that the 

 form in cattle in Somaliland was a variety, T. theileri var. somalensis. 

 It is now known that this degree of variation in the position of the kineto- 

 plast occurs in T. theileri. 



T. theileri is a large trypanosome measuring 60 to 70 microns in length 

 and 4 to 5 microns in breadth, and frequently shows well-marked myonemes 

 (Fig. 210, 3-4, Plate V., m, p. 456). Smaller forms also occur of a minimum 

 length of 25 to 30 microns. It seems reasonable to suppose that the 



