100 MICHIGAN SURVEY, 1905. 



SPIDERS AND INSECTS FROM THE PORCUPINE MOUNTAINS 

 AND ISLE ROYALE, MICHIGAN. 



A. G. RUTHVEN. 



With the exception of the Odonata and Orthoptera, no attempt was made 

 to make extensive collections of the different groups of invertebrates, and 

 the lists comprise only the more characteristic forms in the different habitats 

 studied. The collections were, for the most part, made by the author 

 with the assistance of the other members of the party, except in the case 

 of the ants which were collected largely by Mr. Otto McCreary. We are 

 indebted to the following persons for the determination of the collections: 



Spiders. Mr. Nathan Banks, U. S. Department of Agriculture. 



Dragonfties. Mr. E. B. Williamson, Bluffton, Ind. 



Butterflies and Moths. Prof. Arthur J. Snyder, Springfield, Idaho. 



Ants. Dr. W. M. Wheeler, American Museum of Natural History. 



1. SPIDERS FROM THE PORCUPINE MOUNTAINS. 



1. Gnaphosa conspersa Thor. III. 1. Taken under a pine log among the 

 dwarf huckle-and blueberry bushes in the aspen zone, August. 6. 



2. Linyphia phrygiana Koch. I. Taken on the leeward side of pro- 

 jecting outcrops of rock on the beach of Lake Superior, July 21. Also 

 occurs in Europe (Banks). 



3. Epeira trifolium Hentz. I. This spider occurs numerously along 

 the beach of Lake Superior. It weaves its web behind projecting out- 

 crops of rock, and when surprised runs swiftly into the rock crevices. 

 The webs are often rilled with small white moths, July 30. 



4. Epeira patagiata Clerck. I. This species was found under the 

 same conditions as Epeira trifolium. Also occurs in Europe (Banks). 



5. Lycosa gracilis Bks. III. 1. In a shallow hole in dead grass under 

 a fallen pine log in the aspen zone, August 6. 



6. Pardosa lapidicina Th. I. This species was taken on the beach of 

 Lake Superior, July 30. It was observed quite frequently running about 

 over the rocks, and dodging into the crevices when pursued. 



7. Pardosa. sp. (probably lapidicina). I. Several immature specimens 

 were taken on the rocks of the Lake Superior beach, July 21. 



8. Dolomedes tenebrosus Hentz. II. 1. A specimen of this spider with 

 its egg mass was taken on a cedar stump in the arbor vitae swamp, August 25. 



2. SPIDERS FROM ISLE ROYALE. 



1. Amaurobius sp. V. One specimen was found in the Sphagnum 

 moss in a tamarack swamp, August 22. 



2. Amaurobius bennetti Blackw. II. One specimen was taken in the 

 moss ground cover of the balsam and spruce forest on the flood-plain of 

 Washington river, August 26. 



