THE JOINT-WORM. 555 



straw produced by this worm, led me to suspect that the 

 disease was identical with that which had been observed in 

 barley-straw, and that it originated from the same cause. 

 In the article above named, Dr. Fitch appears to have come 

 to the conclusion that the disease was produced by some 

 species of Cecidomyia. He found the disease of the wheat- 

 straw to be situated immediately above the lower joint, in 

 the sheathing base of the leaf, the substance of which, for 

 a distance exceeding half an inch, was much swollen, and 

 was changed to a more solid and wood-like texture, while 



O ' 



the surface exhibited several long pale spots, slightly elevated 

 like a blister. The hollow of the stem was entirely oblit- 

 erated, at some parts, by the pressure of the enlarged por- 

 tion of the sheath, and was hardly visible at others. Each 

 of the blistered spots covered an elongated cavity, containing 

 a footless worm or maggot, about ten hundredths of an inch 

 long, of an oval form rather more tapering posteriorly than 

 towards the head, and divided by slight constrictions into 

 thirteen segments. The worm was soft, shining, of a uni- 

 form milk-white color, with a small V-shaped brown line 

 marking the situation of the mouth. " So exactly," remarks 

 Dr. Fitch, " does this worm in its form and appearance 

 resemble the larvae of the Hessian fly and other species of 

 Cecidomyia which have fallen under my examination, that I 

 entertain no doubt it pertains to the same genus of insects." 



On the lijth of March, 1852, F. G. Ruffin, Esq., of 

 Shadwell, Virginia, the editor of " The Southern Planter," 

 sent to me that paper for July, 1851, containing some 

 account of the joint-worm, and with it a few samples of 

 diseased wheat-straw. A much larger quantity of the 

 straw, soon afterwards received from him, was divided 

 into two unequal portions, the larger of which was sent 

 to Dr. Fitch, in the hope that between us something defi- 

 nite concerning the origin of the disease might be obtained. 

 Upon examining my samples, I found that the disease 

 was not invariably confined to the sheathing base of the 



