38o 



ScHAUDiNN has traced their further develop. nent in 

 Culex pipiens. The general development is similar 

 to that of T. noctuae, for these also have a trypano- 

 some stage. 



V""".Vr/'"y 



Fig. 86. Development in the blood of Sp. aiemanni and change 

 to vesting forms [after Schaudinn) 



Development in mosquito. 



1. Ookinets of three kinds are developed in the stomach. 



2. From these are developed trypanosomes which, in this 

 case, are minute, and the males so much so that they are very 

 difficult to see except when agglomerated in rosettes. 



3 . The backward and forward movement of spirochaetes 

 results from the fact that two of these trypanosomes, after 

 division, remain attached. 



4. Multiplication goes on in the stomach, and the result- 

 ing forms are so extraordinarily minute that they are "invisible 

 except in agglomerated masses, 



5 . These trypanosomes now penetrate the epithelium of 

 the malpighian tubes, multiply here, and come to rest. They 

 eventually pass out with the malpighian secretion, reach the 

 great curvature of the colon, and then follow the same course 

 as T. noctuae. The mosquitoes can infect a fresh owl after their 

 third meal of blood. 



