106 MICHIGAN SURVEY, 1905. 



collection is a very interesting one. All the forms are subboreal and charac- 

 teristic of the hills or mountains of the northern states or British Columbia. 

 The new Formica [impexa] is especially interesting. Unfortunately only 

 workers are represented. The female is probably an aberrant form like 

 the female of F. oreas or F. ciliata. All the other species are well known, 

 with the exception of F. aserva and Camponotus whymperi. The latter 

 occurs in the mountains of Colorado and British Columbia." 



