g6 
3. Feed some T aeniorhynchus on Proteosoma 
sparrows, and note the negative result. 
4. Feed some Culex upon pigeons containing 
Halteridium , and note negative result {Vide p. 254). 
Sparrows containing Halteridium , so frequently 
(in India) contain Proteosoma that, even if the latter 
is not observed under the microscope, it is difficult to 
be sure of its absence. 
