AMERICAN HYMENOPTERA. 253 



9IOUND-9IAKIXG ANTS OF THE AI.I.EGHE?VIES, 



their Architecture and Habits. 



BY REV. HENRY C. MCCOOK. 



In the summer of 1876 I arranged to make a study of the Wood 

 or Fallow Ants (^Formica ru/a), whose "hills" are familiar to all 

 dwellers and visitors among the mountains of Pennsylvania. The 

 experience of brief observations during previous years had satisfied 

 me that it would be necessary to spend several days and nights on the 

 home field of these interesting mound-builders of the insect world, and 

 observe their habits continuously. Accordingly on Tuesday, August 

 15th, I pitched tent in a grove on the western slope of Brush moun- 

 tain, about one mile northeast of the beautiful city of Hollidaysburg. 

 My companion was James W. Kiddle, Esq., of Bell's Mills, whose 

 generous hospitality and practical aid I have great pleasure in ac- 

 knowledging. John Smidt our cook and flictotum was an intelligent 

 Bavarian who had served in the late Franco-German war. A con- 

 venient and pleasant camping ground was found near *' Bi"' Pine 

 Spring," where we established ourselves and spent a week very com- 

 fortably. My time was wholly given during this period to the in- 

 vestigations, whose results are given below. For the sake of con- 

 venience the name which I gave to the locality, viz. : "Camp Riddle" 

 will be retained in the notes. 



IV limber of Hills.— The field in which we were encamped is the 

 property of the Cambria Coal and Iron Company, and is on the south- 

 west base of Brush mountain. About fifty acres are occupied by the 

 ants. At least three-fourths of this land is covered with an open 

 wood, consisting chiefly of black and white oak, with a i'ew pine, 

 maple, dogwood and hickory trees. The soil is sandy, and is literally 

 filled with the flat reddish-brown quartzoze sandstones which compose 

 the surface bulk of this mountain. 3Iany of the ant hills are sur- 

 rounded by a belt of these stones one to two feet wide, which are 

 quite bare. The soil has of course been transferred from beneath 

 them to the hills, although their peculiur appearance suggests the idea 

 of having been thrown out of a cellar or pit by a human laborer and 

 ranged around the margin. The number of mounds in this "ant 

 city," as it is called by many of the citizens of these parts, is about 

 1700. An actual count was made of 1300, not numerating the embryo 



TRANS. AMER. ENT. SOC. VI. (34) NOVEJIliER 1877. 



