54 



leaf, which of course varies with age and ma}' be the first slender shoot 

 of the plant, or one of the older and tougher tillers of much older 

 plants. This central compactl}^ rolled leaf is cut ofl", the maggot at 

 first working upward until this leaf becomes too tough or begins to 

 wither, when it reverses its position and works downward, where the 

 food supph' is alwa3's fresh and juicy. Pupation does not take place 

 here, but the hirva makes its way when full fed to between the bases 

 of the older leaves, and in that situation the puparia are to be found. 

 A very young plant does not admit of very extended travel by the 

 larva, and in an older one the continuity of its path is soon obliterated 

 by the growth of the plant itself, and the larva is frequently found a 

 couple of inches above the l)ase where it entered after hatching from 

 the egg, as is witnessed by the minute patches eaten out of the leaf. 

 As but a single maggot is found in each stem, 1 have often wondered 

 if the female so distributed her eggs as to prevent a clashing of young, 

 and feel very much inclined to the opinion expressed in some unpub- 

 lished notes by Mr. Pergande to the effect that more than one egg may 

 be deposited about a single stem, but the oldest and strongest maggot 

 kills off the weaker, leaving but one in full possession. 



EXTENT OF RAVAGES. 



Usually the work of this species is so confused with that of others 

 as to render an3^thing like a definite estimate of the damage that can 

 be justly charged to its attacks in the grain fields almost impossible. 

 I have never observed injuries to the full-grown straw, though I have 

 occasionally found larvae in them that I presumed to belong to this 

 species. In fall wheat the plant recovers from a slight injury, espe- 

 cially if growing in a fertile soil, and I apprehend that more damage 

 will follow an attack in fields where the soil is poor or badly worn 

 than where it is richer. In the field of wheat near Wooster, Ohio, 

 that was so severely injured in 1891, the Hessian fly was also present 

 and did full}' as much injury as this insect, both I should say, destroy- 

 ing fully one-half the crop. Dr. Fletcher has called attention to a 

 field of spring wheat in Canada that was damaged fully 75 per cent, 

 for the most part due to the attacks of this species. In the United 

 States, I do not believe that an injury of from 5 to 15 per cent of the 

 crop by reason of the attacks of this and other Oscinis is at all unusual, 

 but this can not in all cases be wholly charged up to this particular 

 species. 



DESCRIPTION. 



The following description of the ^y of Oscinis carhonaria has been 

 kindly drawn up for me by Mr. Coquillet: 



A small, black, two-winged fly having the knobs of the halteres, the feet, and 

 usually both ends of the tibise yellow. Length varying from 1 to nearly 2 milli- 



