420 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



adults of this species will migrate farther than 30 yards from the stubble 

 which marked their emerging place. 



Several fields which were in wheat the previous year were examined 

 and only a trace of the spring generation of this species was found, and 

 this only where the stubble of the previous year's crop had been improp- 

 erly plowed. In one field which was in wheat the previous year, a count 

 was taken 100 yards from the edge and showed no infestation; 150 yards 

 showed an infestation of 0.94 per cent and 200 yards, none. From this 

 it can be seen that by far the greater part of the infestation from this 

 generation occurs in those fields which are adjacent to standing stubble 

 of the pre\dous year's wheat crop and within 30 yards of the edge. 



Plate 17, 3 of the accompanying figures is an illustration of a plant 

 infested by the spring form of this species. The four tillers on the 

 right are infested. The leaves are broader than normal, darker green, 

 and the center shoot is absent. They appear very much as if they were 

 infested by Hessian ^y. The four tillers on the left are normal healthy 

 ones. The isolation of the infestation by the wingless spring generation 

 was very apparent in some of the fields. At the edge adjacent to the 

 stubble the wheat was very thin and dwarfed, which is characteristic of a 

 heavy infestation from this species. Plate 17, 1 and 2 show this condition 

 very well. Both were taken on the same day in the same field only 50 

 yards apart. Both were focused at the same distance. The first genera- 

 tion infestation was 19 per cent and the second generation infestation 

 85 per cent at the spot where the first picture was taken. At the location 

 of the second picture there was none of the first generation found but 

 a second generation infestation of about 50 per cent. 



An examination of the volunteer wheat in the several stubble fields 

 was made and in every case it was very highly infested with spring 

 generation. Where volunteer wheat is abundant in the stubble fields 

 which are harboring the over-wintering pupge, it simply acts as a breed- 

 ing place whereby the wingless first generation can oviposit, thus allowing 

 the strong flying second generation to complete its task of infesting all 

 the wheat in the vicinity. 



Having found that practically all of the first brood was located along 

 the edge (outer 30 yards) of wheat fields adjacent to standing stubble, 

 and in volunteer wheat in the stubble, next it was decided to determine 

 to what extent the winged second generation which came from these 

 infested places could infest the wheat in the surrounding vicinity. 



Counts were made in the same eight fields for second generation 

 infestation but this time, instead of using ten yard intervals from the 

 stubble, 50 yards were used and only four counts made, namely, next to 

 stubble, at 50, 100 and 150 yards. The counts were made similar to 

 those described above, three linear feet of drill row being taken at th ree 



