ECOLOGY OF ISLE ROY ALE. 73 



The butterflies, Basilarchia arthciuis Dru. and Argynnis athtnUs Edw., 

 are so characteristic of these clearings that we knew them by the com- 

 mon name of "clearing" butterflies. The blackflies are abundant, and 

 are preyed upon by dragonflies, probably the chief reason for the occur- 

 rence of them so far from the swamps. 



Of particular interest was the small fly, Hi/drophoriis phUomhrhi^ 

 Wheeler, mentioned before in connection with the rock beaches. They 

 were numerous over all the clearings, but they settled in especial abund- 

 ance on the moist newly exposed soil which I uncovered. It is probable 

 that they do this only for the moisture or coolness, but in one case a 

 number of them swar*med over the pupa case of an ant, (No. C6). 



Of especial interest was the fauna of the large complex of Cladonia 

 clearings just behind the camp at Siskowit Bay. (V, 3), Figs. 2//, 25, 26. 

 There was a unifonm gentle slope from the margin of the bay back some 

 distance inland, on which large areas were occupied by the usual growth 

 of Cladonia, juniper and bearberry. The whole was surrounded and 

 intersected by balsam and spruce forest. 



Shells were quite rare, although a few of the usual species, Polygi/ra 

 alholahris (Say) (233), were collected. 



The subterranean species of ants so common about Rock Harbor were 

 not observed. They were replaced by another species, Formica- fusca 

 L. (223, 224, 226, 227), which built large circular flat-topped nests 

 (Fig. 28), 5 to 8 dm. in diameter, composed of earth and vegetable debris 

 and covered with debris of balsam and spruce needles. Two sizes, a 

 larger (223) and a smaller (224), were sometimes associated in the 

 same nest. Many nests had been almost completely destroyed by the 

 pileated woodpeckers. Spiders, Pardosa sternall.'i Th. (No. 225), were 

 frequently seen crawling over the ant's nests. Other spiders crawl over 

 and through the Cladonia, dragging egg cases behind them, and crawl- 

 ing into holes and crevices. 



Grasshoppers were abundant, as usual. Some short winged nymphs 

 of Melanoplus fasciatus Barnst-VValk., (No. 208) were taken in thickets 

 of Juniperus nana. They usually hide down in the juniper and will not 

 jump out if frightened, but crawl down close to the ground, so that they 

 are practically invisible. When once seen they can be picked up with 

 the fingers. Sometimes they leave the clumps of juniper and jump or 

 fly out over the Cladonia and rocks. These flights seldom exceed 1-2 

 m. in length, but on one occasion one flew 6 m. high and disappeared 

 among the balsam trees. The adults of the same species (193, 201, 

 208, 214), with full length of wings, fly long distances at a height of 

 3-7 m. or more, making the usual clicking noise. They alight only on 

 the bare roQk or on short Cladonia, avoiding the other vegetation. One 

 fiddling grasshopper, Camnnla pellucida Scudd. (No. 228), was also 

 taken from mats of the juniper. 



Bumblebees, particularly Bomhtts terricola Kby. (208) , visited the 

 flowers of Diervilla and Melampyrum. 



Other bees, including Tenthredopsis nehclloidcs McOHl, Coelioxys 

 moesta Cr., XantUosarus mclanopli€a> Sm., and X. latimanus Say, visited 

 the same plants. 



A small carabid beetle, Carabus serratus Kby. (No. 208), crawls over 

 and through the Cladonia, foraging. Leptura chrysoconia Kby. (208) 

 was taken in the same locality. 

 10 i 



