Article II. — An Bcological Study of Prairie and Forest Inverte-brates. By Charles C. Adams, Ph.D. Introductory In four generations a true wilderness has been transformed into the present prosperous State of IlHnois. This transformation has been so complete that in many parts of the state nearly all of the plant and animal life of the original prairie-and forest has been completely ex-terminated. Between the degree of change which has taken place in any given area and the suitability of that area for agriculture there has been an almost direct relation. Fortunately, however, for the preser-vation of prairie and forest animals, the state is not homogeneous, some areas being too hilly, rocky, or sandy for prosperous agriculture. The character and mode of transformation w^hich has taken place in the past is instructive in several particulars because it serves to guide our anticipations as to the future of our fauna. The forested southern part of the state (see frontispiece) was first invaded by trap-pers and hunters, who began the extermination of the larger animals. These invaders were in turn followed by others who, with the round of the season, were hunters or farmers, and continued this exterminat-ing process, particularly in the clearings, which began to replace the forest. These pioneers, men of little wealth, possessed a combination of mental and economic habits which was the result of life in a for-ested country, and naturally they settled in those places most like their former homes — within the forest or near the forest margin. From these settlements they looked out upon the prairies as vast wastes to be dreaded and avoided. As a result of this attitude toward the prai-ries, it required some time, even a new generation, some economic pressure, and a change of habits before the prairies were settled. Mean-while the northern part of the state was yet a wilderness; but through the influence of the Great Lakes, as a route of communication with the populous East, a rapid invasion of settlers set in from that direc-tion. Though these settlers also came from a wooded country, they were more wealthy, settled upon a very fertile soil which was favorably located with regard to eastward communication, and they therefore progressed more rapidly than the less favored, more isolated southern invaders on the poorer soil ; consequently they spread from the forest
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