INJURIOUS INSECTS OF 1903. 



It has seemed to the writer that the flax seeds found in the 

 stubble in the autumn would hardly account for the immense 

 .injury done the crop of the succeeding year, unless the fly was 

 more than one brooded, and hence special attention has been 

 given during the season to determine this point. From the fol- 

 lowing facts it is believed that the occurrence of more than one 

 brood is placed beyond the shadow of a doubt. For a better 

 understanding of the following the reader should be told that the 



Fig. 2. — Larva of Hessian Fly in first 

 stage. Enlarged 50 times. Original. 



Fig. 3. — Larva of Hessian Fly in second 

 stage. Enlarged four times. Original. 



so-called "flax seed'' is a puparium formed by a hardening of the 

 skin of the maggot. 



On June 25th larvae in the second stage were found on stalk 

 just above first joint in Panola township, Chisago county, 

 brought to laboratory and placed in breeding jar where they 

 shortly formed puparia. On July ist more maggots were found 

 in second stage in Clay county ; in one case four individuals 

 being discovered on one stalk just above second joint. These 

 were placed in breeding jar, and July 8th changed to puparia, or 



