ON THE SUBJECT OF PLAGUE 
4. The claws in P. cheopis are small in comparison with 
those of P. irritans. 
5. Two mandibles slenderer and longer than in P. 
irritans. 
Another flea which might be noticed in passing is the 
Pygiosylla ahalae, which is the outdoor flea, commonly found 
on field-rats. It is said to be unimportant in regard to the 
spread of plague from one native dwelling to another ; but as 
the house- and field-rat come into fairly intimate connection 
