OF BLOOD-SUCKING INSECTS AND THE DISEASES THEY TRANSMIT. 299 
Although improbable, it is quite possible that further new species may be 
found, and to allow for this contingency I have added at the foot of the plate 
several symbols which could be used in the respective colours if necessary. 
Further it must be noted that observers well acquainted with the genus 
Glossina but unaccustomed to differentiate the various species often record such 
under the general term “tsetse.” These records obviously could not be included on 
maps which show only species in detail according to this scheme, but at the same 
time it is advisable to indicate them for the guidance of others who may visit 
the same locality and also to show the range of the genus. For these reasons I 
have added on the plate a symbol in black which could be used to indicate the 
presence of undetermined species of Glossina. 
