The Zoologist — January, 1871. 2431 



cell, wliich is situate in llie internal substance of the stem of tlie 

 affected plant, usually a short distance above the first or second 

 knot from the root. . 



"The damage occasioned by the joint-worm is, in certain 

 seasons and in certain localities, ruinously great. In the year 1851, 

 throughout a large part of Virginia, ' many crops of wheat were 

 hardly worth cutting, on account of their attacks.' The loss 

 occasioned by this insect often amounts to one-third of the average 

 crop, and is sometimes much greater; and in 1851 ' some farmers 

 did not reap so much as they sowed.' In 18G0 the rye crop was 

 considerably injured in Lycoming Co., Pennsylvania, and the 

 species is very common upon rye in Connecticut, and probably 

 the other New England States. As long ago as 1829 it had been 

 noticed in various parts of New England to attack the barley, 

 although since that lime it does not appear to have been materially 

 troublesome in that region. But in Central New York, formerly 

 the great barley-growing district of America, it has been ruinously 

 destructive to the barley since about 1850. In Canada West, in 

 the neighbourhood of Grimsby, it was very abundant upon barley 

 in the years 18(56 and 1867. It is a curious fact that — so far as 

 can be at present ascertained — this destructive insect does not 

 seem to have reached the Valley of the Mississippi. It is very 

 possible, however, that the joint-worm may have been confounded 

 in the West with the Hessian fly {Cecidomyia Desiniclor, Say), the 

 larva of which infests precisely the same part of the wheat plant, 

 namely, the space immediately above one of the lowermost knots in 

 the straw. But this last may be distinguished from the joint-worm 

 by living in the open space between the stem and the sheath of the 

 blade, although it occasionally imbeds itself pretty deeply in the 

 external surface of the stem; whereas the true joint-vvorm always 

 inhabits a smooth egg-shaped cell in the internal substance of that 

 stem. 



"It may also seem a strange thing that — so far as is known — the 

 joint-worm should in Virginia attack wheat exclusively, and in 

 New England barley exclusively. This, however, may be partly 

 due to the fact that but very little barley is grown in Virginia, and 

 but very little wheat in New England. The senior editor of this 

 journal (Dr. Walsh) published in the 'Canada Farmer' for 1867 a 

 letter on the barley joint-worm, in which he disavowed and 

 repudiated his former scepticism (as given to the world in the 



