HYMENOPTEIIA. 443 



like others of the same genus, it is provided with an exsertcd 

 slender piercer, nearly as long as its own body. The latter is 

 about as long as that of the Pteromalus above described, and 

 is of a deep black color, slightly tinged with green on the face 

 and thorax, both of which are rough and opaque, while the 

 hind body is smooth and polished. The fore wings have an 

 elongated cloudy spot near the middle, and the oblique branch 

 is very short. The thighs, claws, and the antennee except the 

 basal joint, are blackish, the other parts of the legs and the 

 base of the antenna; are pale yellow. The hindmost thighs 

 are nmch thicker than the others, and are notched beneath the 

 end. The eyes have a dull reddish tinge, perhaps not their 

 true color in life. Professor Cabell has sent to me some speci- 

 mens of this Torymns, including a male, which differs from the 

 female in having all the joints of the antennae black. 



The ravages of the joint-worm in the wheat-fields of Vir- 

 ginia are said to have been first observed in Albemarle county, 

 about four or five years ago. They have alarmingly increased 

 from year to year, and have extended over many parts of the 

 adjacent counties, becoming more aggravated each time that 

 they are renewed in the same place. The loss occasioned 

 thereby often amounts to one third of the average crop, and 

 is sometimes much greater; and during the present season, 

 "some farmers did not reap as much as they sowed." These 

 statements are made chiefly on the authority of Professor J. 

 L. Cabell, of the University of Virginia, who has given some 

 attention to the natural history of the joint-worm, and has 

 recently communicated to me the result of his interesting 

 observations. He has come to the conclusion that the joint- 

 worm is the larva of a Hymenopterous and not of a Dipterous 

 insect. He finds that the parts of its mouth are very different 

 from those of the dormant larva of the Hessian fiy (the latter 

 extracted from its flax-seed case before it had undergone any 

 change of form), and that the mouth of the former agrees 

 essentially with that of the larvae obtained from galls of the 

 oak. In the mouth of the joint-worm he observed that "the 

 mandibular hooks cross each other on the middle line," while 

 in the Hessian "fly larva the " two hooks are directed down- 



