LEPOPJDzE— EPIDEMIC DISEASES. 371 



or from the severity of the weather, if they do not actually excavate them 

 themselves. This is a well-known habit, in many localities, of our common 

 so-called Gray Rabbit (L. sylvaficus), and also of the Lepus campestris, or 

 so-called Prairie Hare. At localities where L. amcricanus and L. sylvaticus 

 occur together, the former is often designated as the Hare and the latter as 

 the Rabbit. Perhaps, however, the one is oftener called White Rabbit and 

 the other Gray Rabbit. Gray Rabbit, perhaps from long familiarity with the 

 same, seems to sound more euphonious than Gray Hare; Marsh Hare than 

 Marsh Rabbit ; and Jack Rabbit' or Jackass Rabbit than Jack Hare or Jackass 

 Hare ; and, however philologically or technically wrong it may be to apply the 

 term Rabbit to any of our wild species, the custom of so doing among the 

 generality of our people is doubtless as ineradicably fixed as is that of calling 

 the American Bison a Buffalo. 



EPIDEMICS AMONG THE NORTH AMERICAN SPECIES OF HARES. 



Nothing is better known to attentive observers of our Mammals than 

 the fact that certain species, especially of the Rodentia, are for a period of 

 years often exceedingly abundant, these periods being followed by succeeding 

 years of scarcity. This is especially observable among the Field Mice (partic- 

 ularly in the case of Arvicola riparius), the Squirrels, and the Hares. Their 

 decrease resuljts usually from some not very obvious cause, though sometimes 

 supposed to l)e connected with a series of unusually severe winters. That 

 this is not the sole cause of their decrease I have been for a long time con- 

 vinced, but that it is due more to some prevalent epidemic. The evidence 

 of this is not generally easily obtainable, but proof of it in other cases is 

 quite abundant. In the case of our little Wood Hare (Lcpus sylvaticus), I 

 have repeatedly met with their dead bodies in the woods and thickets, bear- 

 ing no mark of a violent death, and noted the scarcity of these animals during 

 the years immediately following. I have also observed the same thing in 

 respect to our common Meadow Mouse (Arvicola riparius). I find also 

 recorded in my notes a remarkable decrease, some years since, of the large 

 Long-eared Hares {h.callotis var. texianus and L. campestris) in the Great Salt 

 Lake Valley. This decrease was also accompanied by the finding of great 

 numbers of the animals dead on the Sage-brush plains about the lake, showing 

 no signs of a violent death (of which tact I was abundantly assured by the 

 residents of the region in question), leading to the conclusion that their death 



