388 The Development of Trypanosomes in Tsetse Flies. 



Conclusions. 



1. That Trypanosoma gamhiense multiplies in the gut of about one in every 

 20 Glossina palpalis which have fed on an infected animal. 



2. That the flies become infective, on an average, 34 days after their first 

 feed. 



3. That a fly may remain infective for 75 days. 



4. That Trypanosoma dimorphon, Trypanosoma vivax, and Trypanosoma 

 nayiuvi may also multiply in Glossina palpalis, which must therefore be 

 looked upon as a possible carrier in these diseases. 



5. That multiplication in the tube of the proboscis is characteristic of 

 Trypanosoma vivax. 



Colour Blindness and the Trichromatic Theory of Colour-vision. 

 By Sir William de W. Abney, K.C.B., D.Sc, D.C.L., F.E.S. 



(Eeceived January 21, — Read February 24, 1910.) 



[This paper is published in Series A (No. 565), vol. 83.] 



