554 HYMENOPTERA. 



of the disease, would prove to be some species of Cecidomyia, 

 allied to, but distinct from, the Hessian fly ; and that they, 

 while in the larva or pupa state, had been preyed upon and 

 destroyed by the Ewytoma, The larvae of the Hessian fly 

 are often destroyed by a somewhat similar Chalcidian para- 

 site, great numbers of which have been observed, in their 

 winged form, in wheat- fields, and have then been mistaken 

 for Hessian flies. 



The body of the Eurytoma Hordei is jet-black, and slightly 

 hairy. The head and thorax are opaque, and rough with 

 dilated punctures. The hind body is smooth and polished. 

 The thighs, shanks, and claw-joints are blackish ; the knees, 

 and the other joints of the feet, are pale honey-yellow. The 

 females are twelve or thirteen hundredths of an inch loner. 



o 



The males are rather smaller, and are distinguished from the 

 females by the following characters. They have no piercer. 

 The joints of their antenna) are longer, and are surrounded 

 with whorls of little hairs. The hind body is shorter, less 

 pointed behind, and is connected with the thorax by a longer 

 stem or peduncle. These insects are very active, and move 

 by little leaps ; but the hindmost thighs are not thickened. 

 About eight years ago, some of these insects, that had come 

 from a straw bed in Cambridge, were shown to me. They 

 had proved very troublesome to children sleeping on the 

 bed ; their bites or stings being followed by considerable in- 

 flammation and irritation, which lasted several davs. So 

 numerous were the insects, that it was found necessary to 

 empty the bed-tick and burn the straw. Since that time, 

 I have heard nothing more either of the insects or of the 

 disease of barley-straw in this part of the country. 



My attention was again called to the history of the barley- 

 straw insect by an article on the joint-worm, published at 

 Albany in " The Cultivator," for October, 1851. The ac- 

 count given in this magazine, by Mr. Hives, of the ravages 

 of the joint- worm in the wheat-fields of Virginia, and the 

 remarks by Dr. Fitch on the peculiar affection of the wheat- 



