328 MICHIGAN SURVEY, 1908. 



H. A. G. Also specimens from a single colony on Mackinac Island 

 (3, H. A. G.)- "A common ant on the jack pine ridges (I, .">, SO, 81, 

 100, 102). It constructs its nests under rocks in moist soil (100) and 

 was observed to capture beetle larvae (103). The specimens collected 

 in the rock-clearings at Siskowit Bay ( \', 3, 223, 221, 220, 227), con- 

 structed circular, flat-topped craters 6 dcm. in diameter, covered with 

 debris of balsam and spruce needles and frequently with growing plants 

 on them." This is the common form of the circumboreal F. fuscn 

 throughout Canada and the northern states. At higher altitudes on 

 the Rocky Mountains it passes into the more silvery red-legged var. 

 fiir/cntata Wheeler, a form which also occurs even near sea-level but 

 very sporadically in the Atlantic States. 



9. Formica fusca L. var. neorufibarl)is Emery. A few workers from 

 two colonies: 15 (I, 1) and 20 (I, 1) H. A. G. in vials with sijecimens 

 of Lasiiis neoniger and Camponotus whymperi. Of the numerous 

 varieties of F. fusca this is the most boreal, being known only from 

 Alaska and British America as far east as Labrador and Nova Scotia, 

 and from higher altitudes in the Rocky Mountains (9,000 to 12,500 

 feet). It forms rather small colonies under stones and logs in moist 

 or shady places. 



10. Caiiiponotus herculean us L. var. whymperi Forel. Workers 

 from 10 colonies, with larvae and punae: 15 (I, 1), 18 (I, 1), 22 

 (T, 1), 30 (I, 1), 62 (I, 2), 140 (I, 3) H. A. G. and 105 (V, 2), 126 

 (V, 11), 148 (III, '04), 149 (III, '04) C. C. A. "Although an abund- 

 ant species on the rock and gravel beaches (15, 18, 22 H. A. G.) where 

 it forages for dead insects, its actual home appears to be the ridges.: 

 On the dry ridges it occurs singly, usually in soil under stones (62, 

 H. A. G.). It was also collected (140 H. A. G.) in the dense balsam 

 fir woods, where it forages over the surface. This variation in habit 

 leads to the conclusion that it belongs properly to the rock ridges."" 

 Like the preceding variety of F. fusca, G. tohympcii is a truly boreal 

 ant. It is our North American representative of the typical paleo- 

 boreal C. herculeanus and in the United States is known to occur only 

 at considerable elevations in the Rocky Mountains (above 8,000 feet) 

 and on the summits of the Green Mountains of "Vermont. The types 

 of whymperi were taken in the mountains of Alberta, B. C, by the noted 

 mountain climber, to whom the variety was dedicated. I have seen 

 specimens from Nova Scotia (Russell) and Labrador (Henshaw). 



The foregoing series of Formicidae, though represented by only ten 

 different forms, is of considerable interest on account of its pronounced 

 boreal character. Only two of the forms {Formica suhsericea and 

 Tapinoma sessile) are abundant at ordinary elevations in the northern 

 states. 2[yrm.ica can-adensis, Leptothorax canadensis, Formica asrrva. 

 F. ohscitrirentris and Lasiiis neoniger occur sparingly in the same 

 region, but always in situations which indicate that they are not in 

 their optimum environment or station, or where they seem to represent 

 the laggards of a wave of post-glacial migrants to more northern lati- 

 tudes or higher altitudes. F. adamsi, F. neorufiharhis and Camponotus 

 whymperi are exquisitely boreal ants of circumscribed alpine distribu- 

 tion in the United States, but probably of extensive range in British 

 Amoi-ica. 



