ECOLOGY OF NORTHERN MICHIGAN. 105. 



it also differs from the typical microgyna. The erect hairs on the gaster 

 of impexa are much more robust and obtuse than in the latter species. The 

 new species also resembles F. difficilis Emery and notably its var. consocians 

 Wheeler, except in pilosity and the absence of any yellow color on the basal 

 gastric segment. 



''It is very probable that the female of F. impexais aberrant, either in being 

 very diminutive like the females of F. difficilis and F. microgyna or in having 

 an unusual color like the female of F. areas. Until this sex of impexa is 

 discovered there may be some doubt as to whether the form should be re- 

 garded as a species distinct from rufa. That it differs very markedly in 

 pilosity from all the hitherto described subspecies and varieties of rufa, there 

 can be no doubt." W. M. Wheeler. 



2. Formica fusca L. var. subsericea Say. III. 6. On the rocks at the foot 

 of the talus slope and at the foot of the cliff, August 12. Also found in an 

 ant hill in the clearing, II. 3, and under the loose stones on the mountain 

 top, III, August 6. 



3. Formica fusca L. var. argentata Wheeler. III. 1, 2. A number of 

 colonies were found under the loose rocks on the mountain top, especially 

 among the heath plants. 



4. Formica fusca L. var. neorufibarbis Emery. II. 4. A colony of this 

 species was found in a decaying aspen log, August 8. 



5. Formica lasioides Emery, var. picea Emery. III. 2. Collected under 

 the loose stones on the mountain top, August 11. 



6. Brachymyrmex heerii Mayr. subsp. depilis Emery. III. 6. Under 

 stones on the mountain top, August 12. III. 2. Taken among the heath 

 plants on the mountain top, July 18. 



7. Tapinoma sessile Say. (small var.). III. 1. Under the stones in the 

 aspen zone near the top of the first range, August 11, and on III. 6, under 

 the loose stones on the side of the mountain near the top on August 12. 



8. Camponotus herculeanus L. var. whymperi Forel. III. 2. A colony 

 was found in a dry decaying pine log on the bare mountain top, August 6. 

 and in a decaying pine log on the mountain top, III. 6, August 12. 



9. Lasius brevicornis Emery. III. 2. Beneath the loose rocks on the 

 mountain top, August 11. 



10. Spenamma (Aphaenogaster) fulvum Roger, var. rude Emery. III. 6. 

 Collected beneath the stones near the top of the mountain, August 12, and 

 under stones and fallen pine logs in the aspen zone near the top of the ridge, 

 August 6. 



6. ANTS FROM ISLE ROYALE. 



1. Formica sanguinea Latr. subsp. aserva Forel. I. One colony found 

 in the clearing, August 18. 



2. Formica fusca L. var. subsericea Say. I. Several colonies were 

 found in the clearing, August 18. 



3. Formica fusca L. var. neorufibarbis Emery. I. In the humus beneath 

 a decayed stump in the clearing, August 18. III. In a decayed log on the 

 top of the ridge, August 20. 



4. Camponotus herculeanus L. var. whymperi Forel. I. Found on sides 

 of a log shack, August 18, and feeding on a fish head in the clearing, Sep- 

 tember 1. 



5. , Leptothorax canadensis Prov. var. I. One colony found in the 

 clearing, August 18. 



Dr. Wheeler makes the following comments on the collection: "The 

 14 



