134 MINNESOTA BILL BUGS. 



Only a crumpled, wounded stalk here and there succeeded in niakiny 

 any growth to speak of. About one acre, which was higher than 

 the rest, in one corner of the field was found not to be infested. 



From obser\-atinns, it appears that the emergence of the adults 

 in the spring is controlled by both temperature and moisture condi- 

 tions. ( )n jtme *^ l*^'ll, they were fotmd feeding upon young corn, 

 just out oi the ground, wliile un June 5, l'U2, the beetles had already 

 accomplished their work of destruction of the second planting. On 

 May 29, 1913, much of the corn was from one to three inches high. 

 The adult beetles were \ery few and very hard to find. .Some of 

 the Corn showed old feeding punctures which would ])lace the ap- 

 pearance of the adults at about May 27. 



Many instances were found where the adtilts were feeding 

 upon exposed, unsprouted corn and partly bttried, sprouted corn. 

 .So far as observed, only the starchy portion w^as eaten. In one 

 instance, five beetles were found feeding upon a single kernel that 

 was l)uried three inches lielow the surface. During May and early 

 June it was noticed that they traveled on foot. Not a single instance 

 of flight was observed by the writer. No copulating was observed 

 in the early season but, l)eginning in the fore part of Jtme, mating 

 was obser\ed. and was at its height in July. 



From a Ujt of adults collected on May 2'Jth, it was found that 

 *lieir axerage life period from time of emergence in the spring until 

 death is approximately fifty-eight da_\s. 



Observations showed that not everv liill was infested e\cc]it 

 in severe \ears, but when infested, from one to three a.dults were 

 found to a hill. The largest number found was thirteen. ( )n July 

 5, 1912, after a rainstorm, twenty adults were found feeding upon 

 one ear of corn that was partially buried in the soil, and forty-three 

 upon another similar ear. When feeding upon the corn plant, they 

 generally fastened themselves, head downward, from the le\el of the 

 soil to one and one-half inches above the soil, on the shad}- portion 

 (if the plant. The head is kejjt moving a little from side to side ;ind 

 backward and forward, until a deep slit is made, one or more slits 

 often resulting in the death of the corn plant. Whenever the sun 

 '^Imne Imt and the soil was beginning to dry, the bill I'Ugs would 

 bury themselves from a depth of just below the level of the soil to 

 one and one-half inches deep. Travel would also cease on very 

 drv davs. When clinging to the stalk and disturbed, they readily 

 feign death and are usually quite hard to ])ull off, especially it dis- 

 turbed wdiile feeding. 



