436 INSECTS INJURIOUS TO VEGETATION. 



covered parasite, was Euryioma Hordei, so called from Hordeum, 

 the Latin name for barley. It is very much like the parasite 

 (Eurytoma destructor) of the Hessian fly, described by Mr. 

 Say, but is rather larger, of a jet black color, except the legs, 

 which are blackish, with pale yellow joints. The head and tho- 

 rax are somewhat rough, and slightly hairy ; the hind-body is 

 smooth and polished. The female is thirteen hundredths of an 

 inch long ; the male is rather smaller. It often moves by little 

 leaps, but the hindmost thighs are not thickened. This minute 

 insect is to be reckoned among our friends, being appointed, by 

 an all-wise and provident Creator, to check the increase of the 

 destructive fly that attacks our barley. Though disappointed in 

 my attempts to obtain the latter, in its perfected state, I hail with 

 pleasure the appearance of its mortal enemy. 



Although the barley-fly has not yet been seen by me, there 

 does not exist the smallest doubt in my mind that if is a two- 

 winged gnat, like the Hesaian fly and wheat-fly. Any one, who 

 will compare the history of the two latter with what is known of 

 the barley insect, will arrive at the same conclusion. Both the 

 Hessian fly and the barley insect attack the culms or straw of 

 grain, which they injure to a great extent ; and both have a simi- 

 lar four-winged parasite appropriated to them. In addition to 

 this statement, the following conjectures, in default of facts, may 

 be offered. It is probable that the barley-fly is a species of Ce- 

 cidomyia, distinct from the Hessian and the wheat flies. That it 

 is of the same genus may be conjectured from its attacking simi- 

 lar kinds of plants, and from its having a similar parasite. The 

 maggots of the Hessian fly live between the sheathing bases of 

 the lower leaves of the culms of the wheat ; but the barley in- 

 sects are found within the stems themselves, and lie concealed 

 beneath the thickened epidermis or outer skin of the straw. 

 Upon this essential difference in the mode of attack I ground my 

 belief that the two insects are not identical ; and this conjecture 

 is still further strengthened by the fact, that the parasite of the 

 barley insect is not the same species as that of the Hessian fly. 

 The barley midge {Cecidomyia? cerealis) of Europe, is said to 

 be very injurious, in some parts of Germany, to barley and spelt, 

 in the straw of which the larvae live in considerable numbers to- 



