June, 1902] 



PSYCHE. 



355 



THE STRUCTURE OF THE NESTS OF SOME NORTH AMERICAN 



SPECIES OF FORMICA. 



BY HERMAN MUCKERMANN, S. J., PRAIRIE DU CHIEN, WIS. 



A few years have elapsed since Profes- 

 sor Auguste Forel made amyrmecological 

 tour through some of the eastern states. 

 A short synopsis of his results was com- 

 municated by him from Faisons, N. C, to 

 the Belgian Entomological Society, Brus- 

 sels. In the very beginning of this re- 

 port, which is doubly valuable, emanat- 

 ing as it does from the pen of a man so 

 thoroughly acquainted with European 

 ant-nests, Prof. Forel expresses his aston- 

 ishment at the remarkable and character- 

 istic structure of the nests in America. 

 "In North America," he says, "with 

 some rare exceptions, the ants do not 

 construct mounds, either of masonry or 

 of other materials." (Psyche vol. 9, No. 



304-305. P- 231-) 



The purpose of tlie following remarks 

 is both to prove by new facts this well- 

 founded statement and to modify it with 

 reference to southwestern Wisconsin. 

 The facts presented will serve at the same 

 time to illustrate in accordance with local 

 circumstances his interesting "theory of 

 domes." 



For the sake of clearness I propose 

 first to examine the exterior stniitiirc of 

 the nests and then to pass over to their 

 interior arratigeineut. 



In the first place, to avoid misunder- 

 standings, we must be on our guard, lest 

 by an American " ant-hill " we under- 



stand something similar to what is meant 

 by Forel and VVasmann when speaking 

 of the ant-hills of Switzerland or Holland. 

 To say the least, ant-hills in this country 

 never have a height and circumference 

 approaching any of those of Europe. 

 I remember well myself to have seen in 

 western Germany, for instance in the 

 Eifel and in Munsterania, ant-hills reach- 

 ing a height of i m. Besides, there can 

 be no question concerning the fact that 

 the less conspicuous ant-hills of America 

 do not even occur as frequently as they 

 may be found, for instance, in the fir 

 plantations of southern Holland. Still it 

 would be a decided exaggeration to apply 

 to this region the remarks of Forel con- 

 cerning the eastern states. "When con- 

 versing with them (Americans) they refer 

 to it (ant-hill) as a great rarity which 

 can be found in such and such a forest 

 twenty or thirty miles away " (/. c. p. 

 231). Here within a radius of five 

 miles I know of at least one hundred so- 

 called ant-hills. The reason for this 

 may be found in the circumstance that 

 hereabouts the ants are subject to less 

 disturbance. In any case, it remains an 

 established fact that ant-hills are far less 

 numerous here than in Europe. 



The ant which really erects regular 

 hills is precisely a species not occurring 

 in the east, as Forel justly remarks, 



