514 



FAMILY: TRYPANOSOMID^ 



become infected with T. leivisi by eating the faeces of infected fleas, a 

 method of infection which is probably applicable to other trypanosomes 

 also. 



Attempts have been made to infect invertebrates with the pathogenic 

 trypanosome by inoculating blood from infected vertebrates. Wendel- 

 stadt and Felmer (1909) proved that T. brucei could survive in the tissues 



Salivary glands. Second phase of multipli- 

 cation. Free-flagellated fusiform critliidia, 

 producing infective trypanosomes. 



Hypopharynx. 

 Used as passage 

 only. 



Labial cavity. U.<-ed 

 as passage only. 



loventriculus. End 

 of first phase. Long 

 slender free • flagel- 

 lated trypanosomes. 



Mid gut. First phase of multipli- 

 cation. Free-flagellated fusiform 

 trypanosomes. No crithidia. 



Fig. 217. — Diagnostic Characters of Trypanosoma bmcei and Trypanosoma 

 gambiense in the Tsetse Fly. (After Lloyd and Johnson, 1925.) 



Z 



Preinfective and 



.infective in Lumen 



of hypopharynx. 



Salivary glands. No phase. 



Hypopharynx. Preinfective forms 

 enter and become infective In- 

 fective forms F, cuinulate. 



Labial cavity. Second phase of 

 multiplication. Loosely fixed 

 colonies of ribbon-shaped cri- 

 thidia, aflagellate or almost 

 so, producing free - flagellated 

 slender posterior-nuclear prc- 

 infected forms. 



Froventriculus. End 



of first phase. Long 



slender free-flagc'.lated 



trypanosomes. 



Mid gut. First phase of multi- 

 plication. Ribbon-shaped try- 

 panosomes, aflagellate or almost 

 so. No crithidia. 



Fig. 218. — Diagnostic Characters of Trypanosoma congolense in the Tsetse 

 Fly. (After Lloyd and Johnson, 1925.) 



of beetles for at least seven days. More recently Iwanow (1925) has found 

 that T. equiperdum will live for eleven days in caterpillars {Galleria mel- 

 lonella) kept at laboratory temperature. Active trypanosomes were seen 

 up to the ninth day, while mice could still be infected by inoculation of 

 the tissues of the caterpillars up to the eleventh day. 



