ECOLOGY OP ISLE EOYALE. 159 



was very thoroughly infested with beetles and their Hymenopterous 

 parasites. The surrounding forest was largely White Spruce and Paper 

 Birch. Xylotrechus was particularly abundant at this place. 



Other open places, as those bordering the beach (V, 2) or the small 

 openings on the ridges (I, 2 ) , produced, in addition to the wandering 

 flower feeders Buprestis striata and Blordellestina scapularis, a few 

 Carabids, as Harpalus megacephalus and Pterostkhus femoralis. 



Tn the Balsam, White Sprace and White Birch forests (I, 3 and V, 

 4) the Staphylinids, Grophoema, Boletohiiis cincticolKs, the Erotylids, 

 Tritoma and the Carabids, Galathus and Blechrus, are characteristic. 

 The moist conditions which favor fleshy fungi show a marked influence. 

 Here in the forest, of course, must also belong a great number of wood 

 and bark boring beetles, which our limited collecting found assembled 

 in the sunny openings on flowers. 



Along the Desor trail (III, '04), through the hardwood forest of 

 Yellow Birch, aspen and Sugar Maple, two other Staphylinids were 

 found, Quedius fulgidus and Tachinus memnoius and the Scarabaeid 

 Oeotrupes blackhurnii. 



If now we turn to the lakes and bogs, a very different kind of beetle 

 life is found. On the surface of Siskowit Lake (V, 6) were found 

 Gyrinus inlnutus and picipes and in the water-lily margins of ponds 

 and lakes were found (III, 5 and IV, 3) Donacia proximo-, cincticornis 

 and Galerucella nymphaeae. In the tamarack and arbor vitae swamps 

 (I, 4, 6 and V, 5) the following species of water beetles were found: 

 Hallplus ruficollis, Hr/droporus tristis, Agabus congener and Scutop- 

 terus hornii. 



These may seem very elementary and commonplace observations, but 

 the principles which underlie the correlation of certain (even common) 

 species and their environmental conditions are very generally ignored 

 by students of local faunas, except for collecting purposes. To know 

 the exact habitat of certain species in one locality does not by any 

 means prove that the subject is exhausted for other localities. 

 No general ecological treatment of our beetle fauna has been attempted, 

 not even of the smaller groups, such as families or genera, or even 

 for a local area. The nearest approacli we have to such work is found 

 in certain economic papers, devoted to insects affecting some particular 

 plant. Here is an excellent field for investigation. 



Before leaving the subject of habitats, attention should be called 

 to certain publications which are of particular use in the study of the 

 life histories of insects in these northern forests. The first is Packard's 

 "Forest Insects," and the second is Felt's "Insects Affecting Park 

 and Woodland Trees." 



A few suggestions are added as to methods of ecological collecting 

 which may aid similar surveys. When the time for a suiwey is limited 

 some system of ecologic trapping will prove of great advantage. Thus 

 for aquatic beetles traps, like those planned by Needham, may be very 

 useful; and still others are needed for the ground fauna and those 

 frequenting trees and shrubs. Sweeping and beating as usually prac- 

 ticed, while securing many species, certainly produce little ecological 

 data. It may be suggested that systems of trapping may be devised 

 which will contribute much valuable ecological information. 



