Report of the State Geologist. 673 



plains of Kansas ; and it is quite as likely tliat it had its 

 origin in some of the fertile valleys or grassy plains of 

 Nebraska. 



That its native place is far west of the Mississippi no one 

 can doubt. That it is a great lover of the potato plant is 

 equally certain ; yet it can exist upon other food when pota- 

 toes fail, but first selects the tomato and other plants nearly 

 allied in properties to the potato leaf; but such plants are 

 seldom attacked until the potato fields are fully devastated. 

 The eggs of this beetle are deposited, to the mimber of seven 

 or eight hundred, by each female, at intervals during from 

 twenty-five to forty-five days, on the leaves of the potato, in 

 regularly arranged clusters of from twenty to thirty eggs 

 each. They are of an orange color, and always on the 

 under side of the leaf. In about one week after they are 

 deposited they hatch into larvae, which feed upon the foliage 

 about two weeks, though some fix the period at seventeen 

 days. Their growth is quite regular, and when full grown 

 they are tliree eighths of an inch in length. Upon their 

 sides they have two rows of slight protuberances tipped with 

 black, ten in the lower row and nine in the upper ; when full 

 grown there is a faint trace of a third row below the 

 two, and four black dots, forming the back of the neck, or 

 thorax as it is more properly called in the insect. Its head 

 is also black, and it has a black ring round its thorax. It 

 has six legs, the first pair coming out of the thorax, and the 

 others immediately behind, or on the front part of the abdo- 

 men. Its body is cream color. When full grown they 

 descend to the ground, where they change into a pupa state 

 22 



