26 



itself. In 1885 Professor Cook described Isosoma nigrum., which he 

 states was reared from larvae forming creases and hardened deformities 

 in the straw. Professor Cook's specimens, sent to Washington, have 

 been determined by Doctor Howard as Isosoma iritici Fitch." (See 

 also Walsh, Trans. 111. St. Agl. Soc, vol. .5, pp. 485-490, figs.) 



LIFE HISTORY. 



The larvae pass the winter in the straw, if in wheat, and in the stems 

 of Virginia lye grass {Elymus vlrginicus) in the East, and U. gJaucus 

 and another grass, either Bromus ciliatus or a species of Agropj^ ron, 

 in California. 



In the Middle West the adalts appear the latter part of May and 

 early June. The egg does not differ materially from that of /. grande.^ 

 and it is probable that the method of oviposition is much the same as 

 in that species, the female placing her eggs in the 3'oung growing 

 wheat plant just abov^e the uppermost joint to which she can secure 

 access at the time. Ordinarily the upper j.oint is not yet uncovered, 

 except in case of very early wheat, and in that which has made less 

 advance even the second joint from the head is so covered with the 

 sheaths that the insect is unable to determine its position, so that 

 sometimes we find more larvae between the second and third joints 

 than we do farther up between the first and second, precisely as with 

 I. grande. The larv* reach their full growth by harvest, but do not 

 pupate until the following spring. 



All adults are winged, and both sexes are represented. Outside the 

 wheat field I have reared the insect only from Elymus virgmicus., and 

 I question its breeding in the stems of cheat {jB?'omus secalinw<) for 

 the reason that I have reared it from the lye grass and not from the 

 cheat, though both were abundant in the same locality. Mr. Koebele, 

 who reared it from Elymus glaucus in California, was uncertain 

 whether he also reared it from Bromus ciliatus or Agropyron. Both 

 the Bromus mentioned by Koebele and Agropyron repens occur in the 

 East, and it is very probable that future studies of the species will 

 show that there are other grasses besides r3^e grass that will require 

 attention from the farmer who wishes to guard against its appearance 

 in his fields l)y preventing its breeding permanentl}^ along roadsides 

 and the borders of his fields. 



DISTRIBUTION. 



Doctor Fitch received this insect from Maryland, Doctor Lintner and 

 Professor Comstock reared it in New York, the United States Depart- 

 ment of Agriculture has it from Virginia and North Carolina, Pro- 

 fessor Cook reared it in Michigan, I have reared it in Ohio and Illinois 



« Grass and Joint-worm Flies and their Allies, Tech. Ser. 2, Div. Enfe., U. S. 

 Dept. Agr., p. 18. 



