27 



and found it in Indiana, Doctor Fletcher has roared it in Ontario, 

 Canada, and Mr. Koebele in California, and there is hardl}' a doubt that 

 investigations will reveal its presence throughout the entire wheat- 

 growing region of North America. Being fully winged and single 

 brooded, as well as caj)able of breeding in abundance outside of the 

 grain lields, there seems no good reason wh}" it should not cover the 

 whole country, attacking either spring or winter wheat. 



DESCRIPTION. 



^'■Female. — Length 4 mm.; expanse 7.6 mm. Head, pronotum, ana mesonotiim 

 strongly rugulose but not umlnlicate-punetate except toward tip of Hcutellum, where 

 an occasional umbilicate puncture occurs; metanotum also strongly rugulose, with a 

 faint trace anteriorly of a median longitudinal furrow; metanotal spiracles large and 

 perfectly circular; pronotal spots moderately large and often faint, but plainly dis- 

 cernible from above, sometimes, however, quite bright and distinct. Abdomen 

 longer than thorax, nearly as long as head and thorax together; abdominal segments 

 4 and 5 together longer than 2, 3 only about half as long as 4, and 5 as long as two 

 preceding united; first funicle joint one-half longer than second; club longer than 

 three preceding funicle joints together. Body slightly but plainly jiilose except at 

 sides of metanotum, where the fimbria is very obvious. Legs black except at joints, 

 which, with the tarsi, are yellow. Claw of stigmal club given off before the tip. 



Male. — Length, 2.9 mm.; expanse, 6 mm. Petiole shorter than hind coxpc, faintly 

 punctate; flagellum of antennte uniformly pilose, joints well rounded above, not 

 strongly pedicellate; joint 1 three times as long as wide and nearly three times as 

 long as pedicel; none of the funicle joints constricted in the middle; joints 2 and 3 each 

 nearly as long as 1; joints 4 and 5 each a little shorter; rlub plainly divided by a 

 distinct incision into two joints, but the terminal ovate joint is not pedicellate." 

 Howard, Tech. Ser. 2, Div. Ent., U. S. Dep. Agr., pp. 17, 18. 



Originally described by Fitch, Jour, N. Y. State Agr. Soc, 1859, 

 p. 115. Cited as homma liordel ])y Walsh, Amer. Ent. and Bot., II, 

 p. 332. Described as Decatoma hasilaris by Provancher, Faun. Ent. 

 Can., II, p. 569. 



NATURAL ENEMIES. 



The natural enemies are, with few exceptions, probably the same as 

 with the preceding species, to which this is more closely related than with 

 the one that follows, at least so far as its life history is concerned. In 

 my own rearings I have invariably bred this in connection with I. 

 grande if from wheat strawy or with 1. elyml if from grass, so that 

 personally I am not able to say that certain parasites actuall}^ came 

 from I. tritici^ though there is no reason for doubting that such was 

 the case. Certain parasites do most certainly confine themselves to 

 particular species of Isosoma. Wehsterell/us frit lei Ashm. has only 

 been reared from this species, as it is now known. An undescribed 

 Isosoma occurs in considerable abundance in the stems of Tricusjpis 

 sesler'ioidei^, and from this I have reared a parasite belonging to the 

 genus Torymus, but strangely enough this parasite has only been 



