7152 re The American Naturalist. [September, 
20. CROTALOPHORUS CATENATUS CATENATUS Raf. 
This massasauga or prairie rattlesnake is common in east- 
ern and middle Nebraska though we have not found it in the 
` extreme western part of the State. We have examined speci- 
mens from Gage, Lancaster and Nemaha counties, and Dr. 
Yarrow mentions one specimen as from Nebraska. 
We have often kept this snake encaged in our laboratory 
but have never succeeded in getting them to eat. They seem 
to prefer to remain coiled in some dark corner of the cage 
seemingly awaiting an attack. 
The contents of the stomachs of this species show that its 
food is almost wholly made up of mice and other rodents. 
Aside from well-known venomous qualities this snake has no 
bad habits and is decidedly useful. It is said that rats or mice 
will very soon disappear when the presence of this reptile is 
known. In at least one instance we have known this state- 
ment to be true. It was noticed that rats which a few days 
previous had been extremely numerous in a cellar had almost 
wholly disappeared. Within a few days the mystery was 
solved by finding a huge rattler in the doorway. These facts 
fully account for the frequent finding of the rattler around 
old cellars, buildings, etc., where they go to find their choice 
food. 
21. CROTALUS CONFLUENTUS CONFLUENTUS Say. 
This species was formerly abundant all over the State, but 
is now confined almost wholly to the middle and western part 
of the State, where they are by no means rare. We have 
examined specimens from Dawes, Hamilton and Sheridan 
counties. Dr. Yarrow mentions collections made at Pole 
Creek, Neb., Sydney, Neb., and Fort Kearney, Neb. 
Their food habits are similar to C. catenatus. This is the 
species often found in or around the homes of the prairie dogs, 
where they are most abundantly found during the breeding 
season of the dogs. 
