34 CORN AND GRASS. [1899 



form of attack having been reported in this country. Therefore, 

 though now after the experience of thirteen years there appears no 

 reason to fear that we shall be troubled by Hessian Fly as one of the 

 regular crop pests, I have alluded to the infestation again to bring 

 information up to date regarding, firstly, method of winter infestation 

 and its effect on the appearance of the attacked plants ; secondly, the 

 use according to the most modern views of the process beneath the 

 larva, or maggot, known as the "breast-bone," or "anchor-process," 

 more scientifically as the " sternal spatule," of which I gave a figure 

 from life in my Annual Eeport for 1886, p. 15, and repeat it now at 

 p. 37 ; and thirdly, the enormousJy impartant point that in the paper 

 by Prof. Osborn (published under the direction of the Entomologist of 

 the Department of Agriculture of the United States, and forming 

 Bulletin No. 16, New Series, of the publications of that department) it 

 is noted that burning the stubble is one of the standard measures of 

 prevention which is most generally applicable in the United States of 

 America, and also attention is drawn to the desirabilitij of burning 

 chaff and screenings after threshing. These matters are entered on 

 in detail in the following pages. 



The ordinary points of the attack are well known ; but it may just 

 be mentioned again that the Cecidomyia destructor, or Hessian Fly, is 

 a very small two-winged gnat-like fly, hardly as much as one-tenth of 

 an inch in length ; the male one-third shorter than the female; the 

 wings clothed with black hairs or scales ; and the general appearance 

 of the body very dark. When magnified, it will be found to be varied 

 with pink, or red, or yellowish brown, and black, the black being more 

 present in the male than the female.* The bright red colour which 

 the abdomen of the newly-developed female appears to the unassisted 

 eye is very noticeable to trained observers, and it is of considerable 

 interest to watch the gradual alterations of colour. 



The method of attack is for the fly to lay her reddish eggs in the 

 long furrows of the upper surface of the leaves of the Wheat or Barley 

 or Rye. On the hatching of the maggot, which it is stated may take 

 place in about four days, it then, in its first and locomotive state, moves 

 down the leaf, and along within the leaf-sheath, until it reaches a 

 position near the base of the culm, but necessarily differing in position, 

 and in its effect on the plant, according to whether it occurs to the 

 young autumn Wheat, or when the plant is in its summer state with 

 its jointed stem. 



* For long and minutely detailed technical description of male and female 

 Cecidomyia destructor, Say, see account by Mr. K. H. Meade (from living specimens), 

 published in the 'Entomologist' for July, 1887 ; and also given at pp. 15 and 16 of 

 my Annual Eeport for 1887 by permission of Mr. Meade, and of Mr. Newman, 

 proprietor of the ' Entomologist.' — (E. A. 0.) 



