312 Prof. Westwood on the supposed abnormal 



whose observations thereon appeared m ' The Culti- 

 vator ' for October of that year. The disease in this 

 case was found to be situated immediately above the 

 lower joint in the sheathing base of the leaf, the sub- 

 stance of which, for a distance exceeding half an inch, 

 was much swollen, and was changed to a more solid and 

 wood-like texture, whilst the surface exhibited several 

 long pale spots, slightly elevated like a blister. The 

 hollow of the stem was entirely obliterated at some parts 

 by the pressure of the enlarged portion 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-lmndredths 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 an 

 uniform milk-white colour, 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 Cecidoini/ia which have fallen under my 

 examination, that I entertain no doubt it pertains to the 

 same genus of insects." A number of specimens of the 

 diseased wheat were submitted to Drs. Harris and Fitch 

 for investigation, the former of whom only obtained 

 specimens of Eurytoma from them, all with one exception 

 being females ; whilst Dr. Fitch obtained above one 

 hundred specimens of the same Eurytoma, all of which 

 were females. The former observer obtained also one 

 Chalcidian parasite belonging to the genus Pteromalus, 

 whilst the latter also obtained another and different 

 parasite belonging to the genus Torymits, with the hind- 

 most thighs much thicker than the others and notched 

 beneath at the end. 



The ravages of the joint worms in the wheat-fields of 

 Virginia subsequently attracted the attention of Prof. 

 J. L. Cabell, who came to the conclusion that the joint 

 worm is the larva of a hymenopterous, and not of a 

 dipterous, insect. Dr. Harris completes his summary of 

 the history of these insects with the following remarks : 

 — " The foregoing account might be thought to afford 

 conclusive evidence that the Eurytoma alone was the 

 author of the mischief done to the wheat and barley, 

 and that it is not a parasitical insect. In favour of this 

 opinion we have the fact that hitherto no person has 



