84 



INJUKIOUS INSECTS 



pensation, we suppose, it is particularly partial to the 

 stem of tlie common Oocklebur [Xanthium strutnarium); 

 aud if it would only confine itself to such noxious weeds 

 as this, it might be considered as a friend instead of an 

 enemy. Fourteen years ago it was more numerous than 

 usual, and we noticed it to be particularly abundant 

 along the Iron Mountain and Pacific roads in Missouri. 



The larva of the Stalk Borer moth leaves the stalk in 

 which it has burrowed the latter part of July, and descends 

 a little below the surface of the earth, where in about 

 three days it changes into the pupa or chrysalis state. 

 The winged insect (fig. 54, 1), which belongs to the same 



± 2 



Fig. 54.— POTATO-STALK BOREB. 

 1, Moth ; 2, Larva. 



extensive group of moths (JVocttia family, or owlet moths) 

 to which all the cut-worm moths appertain, emerges from 

 under ground from the end of August to the middle of 

 September. Hence it is evident that some few, at all 

 events, of the female moths must live through the winter 

 in obscure holes and corners, and lay their eggs upon the 

 plants which they infest in the following spring. For 

 otherwise, as there are no young ^^otato or tomato plants, 

 or Indian corn, or dahlias, or asters, or even cocklebur 

 for them to lay their eggs ujDon in the autumn, the Avhole 

 breed of them would die out in a single year. When a 

 vine is found to wilt suddenly, it should be examined 

 for this insect, which should be destroyed, to prevent 

 further increase. 



