70 



INJUEIOUS INSECTS 



same pattern is observable, no matter what may be the 

 general color; the body being marked as in figure 41, 

 with longitudinal light and dark lines, and covered 

 with black spots which give rise to soft hairs. Those 

 worms that Mrs. Treat found on green peas and upon 

 corn tassels, had these lines and dots so obscurely repre- 

 sented that they seemed to be of a uniform green or 

 brown color, and the specimens which I saw last summer 

 on string beans were also of a dark glass-green color, with 

 the spots inconspicuous, but with the stripe below the 

 breathing pores quite conspicuous and yellow. The head, 

 however, remains quite constant and characteristic. Fig- 

 ure 40 may be taken as a specimen of the light variety, 

 and figure 41 , a, as illustrating the dark variety. When 

 full grown, the worm descends into the ground, and there 

 forms an oval cocoon of earth interwoven with silk, 

 wherein it changes to a bright chestnut-brown chrysalis, 

 provided with four thorns at the extremity of the body, 

 the two middle ones being stouter than the others. After 

 remaining in the chrysalis state from three or four weeks, 

 the moth makes its escape. In this last and perfect 

 stage, the insect is also quite variable in depth of shading, 

 but the more common color of the front wings is pale 

 clay-yellow, with a faint greenish tint, and they are 

 marked and variegated with pale-olive and rufous, as in 

 figure 41 {Jb showing the wings expanded, and c represent- 

 ing them closed), a dark spot near the middle of each 

 wing being very conspicuous. The hind wings are paler 

 than the front wings, and invariably have along the outer 

 margin a dark brown band, interrupted about the mid- 

 dle by a large pale spot. 



In 1860 — the year of the great drouth in Kansas — the 

 corn crop in that State was almost entirely ruined by the 

 Corn-worm. According to the Prairie Farmer," of 

 January 31, 1861, one county there which raised 436,000 

 bushels of corn in 1859, only produced 5,000 bushels 



