110 THE CANADIAN ENTOMOLOGIST 



forms are western), twelve forms of the palearctic and nearctic 

 truncicola, and nine other species; (3) the Microgyna group, con- 

 sisting of seven forms of the nearctic microgyna, and six other 

 species; (4) The Exsecta group, comprising four forms of the 

 nearctic exsectoidts, seven forms of the palearctic and nearctic 

 exsecta, and two other species; (5) The Fusca group, including 

 fourteen forms of fusca, the typical form of which is widely dis- 

 tributed throughout north and central Eurasia and boreal America, 

 seven forms of the palearctic and nearctic rufilabris, nine forms of 

 the palearctic and nearctic cinerea, and six other species; (6) The 

 subgenus Proformica, including five forms of the nearctic neogagates 



and eight other species, some of them palearctic; (7) A new sub- 

 genus, Neoformica, erected to include the nearctic pallid efidva in its 

 seven forms, and one other species, F. moki Wheeler. 



Dr. Wheeler believes that North America must be the original 

 home of the genus, because it has nearly double the number of 

 species that Eurasia contains, "especially as it possesses representa- 

 tives of the Eurasian groups of species besides two peculiar to itself 

 (the Microgyna group and the subgenus Neoformica). Further, he 

 regards the southern ranges of the Rocky Mountains in the United 

 States as the centre of origin of the genus, for "nearly forty-two 

 per cent, of the New World forms occur in Colorado and the ad- 

 jacent portions of New Mexico," and the colonies of the individual 

 forms are unusually numerous and flourishing on the mountain 

 slopes of this territory. 



Dr. Wheeler modestly makes only short references to the im- 

 portant discovery, in which he took a leading part, that many 

 species, including rufa and exsectdides, form their colonies by 

 temporary social parasitism in small colonies of F. fusca or in a few 

 cases, another species. 'The recently fecundated rufa female 

 rinds a home in a F. fusca colony and permits these ants to 

 bring up her young. The fusca queen is either destroyed by the 

 intrusive rufa or by her own offspring, so that when the fusca 

 workers eventually die off a pure colony of rufa remains." 



F. W. L. S. 



