STATE AGRICULTURAL SOCIETY. 129 



INSECTS INJURIOUS TO AGRICULTURE IN CALIFORNIA. 



BY H. H. BEHR, M. D., 



ENTOMOLOGIST TO THE BOAUD OP AGRICULTURE. 



Cultivation of the soil, whether it be agriculture or horticulture, and 

 even the raising of stock, produces gradual changes in the fauna of a 

 country, and this change takes place most speedily and thoroughly in 

 the insect kingdom. Species which formerly abounded will retire before 

 the husbandman, and take refuge in the mountains or swamps, and 

 others which were at first known to naturalists as extremely rare, will 

 increase and overrun whole districts. 



We have already witnessed this phenomenon on a large scale in Cali- 

 fornia. For instance: Halisidota Salivis (Behr) was ibrmerly very com- 

 mon, and is now nearly extinct. On the other hand, Pi/rameis Carye 

 (Whit.) first made its appearance in eighteen hundred and fifty-two, has 

 multiplied in the vicinity of San Francisco to such an extent that it is 

 now one of the most common species of butterfly. 



It is the constant " struggle for existence" in the animal and vegetable 

 kingdom which produces these effects, and as this struggle goes slowly 

 on, and passes through many phases, the change of species also takes 

 place almost imperceptibly. 



Agriculture can hardlj^ be said to have existed in California for more^ 

 than a dozen years, and of course the balance between the different 

 provinces of creation has as y^t been but slightly disturbed. Some 

 insects Avhich at present are quite rare, may in the future become very 

 troublesome. I give here a catalogue of some species of Lepicloptera 

 which have heretofore proved destructive, and of some others which in 

 the future may do harm. The present is more the time to collect mate- 

 rial, than it is to work out an elaborate treatise on a subject in which 

 our experience is so limited. 



LIST or LEPIDOPTEROUS INSECTS SO FAR KNOWN TO BE INJURIOUS TO 



VEGETATION. 



1. Hdiotlds umbrosus (Grote.) — I can find no difference between the 

 Atlantic insect so destructive of the cotton, and our Californian which 



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