1884.] NATURAL SCIENCES OF PHILADELPHIA. 51 



THE RUFOUS OR TH ITCHING AWT OF DAKOTA AND COLORADO. 

 By Henry C. McCook, D. D. 



During the autumn of 1883, I had a series of conversations 

 with Mr. B. S. Russell, an intelligent business man, resident at 

 Jamestown, Dakota, concerning a species of ant which inhabits 

 that Territory. At first I was inclined to think that the insect 

 which Mr. Russell described was the Occident ant, especially as 

 the popular name which it bears among the pioneers is the 

 " stinging ant," but further details caused me to suspect that the 

 habits described must be those of Formica rufa^ whose nests I 

 had observed in various parts of Colorado. I accordingly entered 

 into correspondence with Dr. R. G. De Puy, of Jamestown, who 

 forwarded me specimens which proved to be Formica rufa. I 

 also gave him a number of points to be noted, and directions as to 

 how to proceed in studying these points ; all of which were fol- 

 lowed up with accuracy and intelligence, that covered all my 

 inquiries. The notes which follow I have written out from the 

 observations of the two gentlemen above named, and those made 

 by myself in Colorado. 



Locality and Site. — The entire rolling prairie country lying 

 between the Cheyenne and James Rivers (Dakota), is dotted with 

 a vast number of ant-hills, which extend westwardly as far as the 

 Missouri River. Mr. Russell could not say whether they are to 

 be seen in the Red River Valley, which, however, is frequentl}'' 

 overflowed. I first met the hills of Rufa on the "Divide," north- 

 eastwardly from Colorado Springs. Subsequently I saw them in 

 South Park, and afterward in the vicinity of Leadville. They 

 were scattered here and there throughout the woods and clear- 

 ings, along the trails and near the diggings, within the limits and 

 suburbs of the " Camp," as the place was then (1879) called, and 

 were struggling with the miners, with varying success, to main- 

 tain their little " claims." I was struck by the fact that these 

 persistent creatures had been able to push up their domiciles to 

 such high sites, and to hold them against the rigors of the winter 

 frosts. 



Specimens sent me from Iowa Gulch, near Leadville, by Mr. C. 

 O. Shields, were taken from an elevation of 11,300 feet above the 

 level of the sea. 

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