392 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



October 0, however, the cricket was again seen at w»rk cutting off 

 young wheat-stems. 



INSECTS AFFECTING RYE. 



All insects observed affecting this grain to any extent have pre- 

 viously been considered under the head of Wheat Insects, and hence 

 it is not necessary to repeat them here. 



I have noted several others injurious in fields of rye, but these will 

 be considered in a later report. 



The two grains, wheat and rye, are so closely allied that any insect 

 found affecting one may be confidently looked for on the other. 



INSECTS AFFECTING OATS. 



Of all our small grains this is the least affected by injurious insects. 

 Many species that are exceedingly destructive to both wheat and rye 

 do not affect oats in the slightest degree. 



A notable case is that of the larva. 1 of the Wheat. and Grass Saw- 

 fly, which will perish of starvation when confined upon fresh, tender 

 shoots of growing oats. 



!No injuries of any moment to this grain have come under my obser- 

 vation, and I shall notice but one insect in relation to it. 



THE STALK-BORER. 



(Gortyna nitela Guen.) 



On the 7th of May, while walking through a field of oats near Bloom- 

 ington, 111., I noticed that the central vertical leaf was, in numerous 

 cases, withering, and in others dead and brown. 



On examination of the affected plants I found that the heart of the 

 stem had been eaten, and I had examined but two before I found a 

 larva of a Gortyna, which in all probability was that of nitela, that 

 was engaged in feeding in the young stem below the surface of the 

 ground. 



The larva3 at this time were from 2 mm to 3 ram in length, and I found 

 them in the interior of the field 10 to 15 rods from the margin, a 

 distance they could by no possibility have traveled. I found many 

 young larvae in the stems of grass along the margin of the field, some 

 of which were larger than those fouud in the oats. I also found that 

 these larvae in the grasses moved from one shoot, as it withered and 

 died, to another, and that the first soon became shriveled and disap- 

 peared, while from its base young shoots at once sxmmg up and took 

 its place, so that the number of affected stems visible at one time offered 

 no reliable data as to the number of larvae infesting the grass or the 

 number of shoots they had destroyed. 



The field under consideration had been planted with corn the pre- 

 vious year, and on the 15th of the preceding month (April) plowed and 

 sown with oats. 



At the time of my observations the grain was about 2 inches high, 

 and had, as yet, but one lateral leaf, and, as near as I could recollect, 

 had made its appearance above the surface of the ground about the 

 22d of April. It is hardly probable that eggs were deposited in this 

 field prior to this time. 



The point at which the larva? had entered the plants wae plainly in- 

 dicated by a small cavity near the lower extremity of the bulb just 



