OF THE FAKM Ai^D GAEDEl^". 



125 



the sheath, as is supposed to have been done in the en- 

 graving, they become at once yery conspicuous objects. 

 We have observed that the ^^internodes," as botanists 

 call them, or the spaces between the knots, in infested 

 straws are always much contracted in length, none out of 

 a lot of oyer fifty specimens examined by us exceeding 

 six inches in length, and many being reduced to only one 

 and a half inch. There were only three straws in this 

 lot of oyer fifty straws, where two Joint- worm galls were 



Fig. 86. — THE JOINT-WORM {Isosonia hordei, Harris). 

 a, Gkills at joints ; b. Female Fly, enlarged, the lines showing the real size. 



found in the same straw; and in all those three cases 

 they were found in two adjoining internodes. In a yery 

 few instances the galls were situated in the middle of the 

 internode, or even close to the upper knot, instead of be- 

 ing situated as usual aboye the lower knot. 



AMOUNT OF DAMAGE DONE BY THE JOINT-WORM. 



The damage occasioned by the Joint-worm is, in cer- 

 tain seasons and in certain localities, ruinously great. 

 In the year 1851, through a large part of Virginia, ac- 

 cording to the Editor of the ^'Southern Planter," 



