INSECT LIFE. 135 



Since the first settlement of the State, 

 The Material Conditions in Relation to Insects 



have greatly changed, and are still in process of change, and more 

 rapidly than ever. Forests have been removed in some places, and 

 planted in hundreds of others. Whole counties have been rapidly 

 transformed from raw prairies to cultivated fields. The old balance 

 between insects and plants has been disturbed. The natural food 

 of the insects has been removed, but the insects themselves pro- 

 bably remained. No alternative then remains but for the in- 

 sects, in accordance with natural law, to adapt themselves to the 

 changed condition. If man takes away their natural food, they will 

 naturally confiscate, or try to, some of his. For the loss of the 

 spontaneous vegetable productions of the State, they find compen- 

 sation in corn fields, vineyards, orchards, gardens, wheat fields and 

 clover and timothy and clover fields. If the new vegetable forms 

 introduced into the State had only native foes to fight, the struggle 

 for existence wouljd not be so severe. But in addition, other foes, 

 old enemies from their native climes, follow them. The apple tree 

 and the vine, the peach and the pear, in their westward march, have 

 gathered the foes of all climes and all lands, until their numbers are 

 legion. 



Friends and Enemies. — Still with the enemies that have accumu- 

 lated, came some friends, often in disguise. Vast numbers of insect 

 parasites often make their appearance to re-establish again the broken 

 harmony of nature. Thus ever changing man keeps nature in tur- 

 moil in her efforts to adapt herself to the newly imposed conditions. 

 Insect enemies sometimes make their appearance and increase with 

 such amazing rapidity as to threaten the entire destruction of some 

 horticultural or agricultural industry. Finally an enemy stealthily 

 makes its appearance, sometimes from the native region of the 

 plant, and sometimes from other lands. The abundance of food 

 favors its rapid increase, until in a few years it has almost wholly 

 destroyed the source of its food, when both fall back to the narrow 

 dimensions, and the obscurity from which they had emerged. This 

 continued disturbance and readjustment of the relations between in- 

 sect life, horticulture and agriculture must, in the nature of things, 

 continue for a generation. This involves the continued need of 

 watchfulness and special labor in the entomological field. We need 

 for our State 



