74 MICHIGAN SURVEY, 1908. 



The yellow clearing butterfly, Basilarchia arthcmis Dru. (208), is 

 very common, flying in regular paths up and down the clearing at a 

 height of about one meter, sometimes alighting on the ground and some- 

 times on the flowers of Opulaster. 



Vrocerus flavicornis Pabr. and U. fiavipennis Kby. (208, 209, 228) 

 Avere especially common. They fly low, usually 2-3 feet above the 

 ground with a moderate but uniform velocity. They are searching for 

 balsam trees in which they deposit their eggs, and were sometimes taken 

 crawling over the trunks. 



A small brown wasp flies low over the ground like an asilid. 



Asilid flies, Asilus annulaki.s Will. (208), fly low, 1-2 ft. above the 

 ground, alight on tufts of grass or Cladonia and crawl down into it. 

 It could not be determined what they were hunting. 



Three species were taken on the flowers- of the harebell, Campanula 

 rotundifolia. They were Coelioxys nivcsta Cr., Xanthosarus melatioplwea 

 Sm. and X. latimanns Say. Insects were more numerous on the flowers 

 of Opulaster, from which were collected Tenthredopsis nrhelloides Mc- 

 nm, ^Prosopis sp., Argynnis atlantis Edw., Eristalis dimidiatiis Wied., 

 Phormia terraeiiovac Desv., P. regina Meis, and Hyetodesmia serva Meis. 



A wasp, Euttypus americanus Cress. (235), was found backing over 

 the ground dragging a spider, Lycosa JcochU Keys. At brief intervals 

 it dropped the spider and ran rapidly back and forth looking for the 

 hole to which it was taking its capture. It seemed to have a general 

 idea of its location, but had to crawl always exactly to it. Having found 

 it, a similar search was begun for the spider, and then the journey was 

 resumed in a direct line toward the hole. 



The typical Cladonia clearings just described were almost invariably 

 on the lower ridges or gentler slopes. They were surrounded, and 

 eventually entirely covered, by the balsam-spruce forest. On certain 

 of the higher or steeper ridges, there was another intermediate stage in 

 which the clearings were covered with jack pine. This was due ap- 

 parently to their position; the formation of soil was slower and the 

 drainage better, so that, even with a considerable depth of soil they were 

 still too dry for balsam or spruce, and were accordingly occupied by the 

 xerophile jack pine. In general ecological conditions they were but 

 little different from the treeless associations. The ground vegetation 

 was, as usual, Cladonia or bearberry, and the forest cover was scarcely- 

 heavy enough to make much shade. But the mere presence of trees 

 indicates that there was a greater deposit of the soil. Under the bear- 

 berry and Cladonia, the soil was quite thin, but there were more loose 

 rocks, and larger and deeper fissures, which were filled with soil. The 

 effect on the fauna was to increase the number of subterranean species 

 a,nd diminish the number of aerial forms. 



In the soil deposits up to 5 cm. deep there is practically no animal 

 life, although ants crawl over the surface. Nests of Lasius niger L. are 

 common in crevices and under loose stones at a depth of 1 dm. or more 

 (Nos. 79, 82). A nest of Lasius niger L. (No. 83) was excavated under 

 and at the side of a large stone. The stone formed the roof of shallow 

 excavations where the pupae were stored, and the vertical wall of earth 

 at the side was honeycombed with rounded passages 1-2 cm. high, 2-4 cm. 

 broad, and separated by thin partitions. Under larger stones their 



