418 THE CANADIAN ENTOMOLOGIST 



to the describer, have a length of 10 to 25 mm. and a diameter of 

 from 1.5 to 5 mm. There may be 1 to 10 galls in an axil, firmly 

 attached to the stem by an expanded base and projecting in vrrious 

 directions, usually upwards, often at right angles to the stem and 

 occasionally downward. They occur on the upper third of the 

 stems of Helianthiis decapetahis and H. divaricatus , growing in 

 open woods or in shaded situations. This gall occurs about Tor- 

 onto, Ont., and has been collected at Evanston, 111., by Mr. L. H. 

 Weld. A species of Torymus has been obtained from this insect. 

 Specimens of this midge were reared June 23, 1907, by Dr. A. 

 Cosens, of the University of Toronto. The following descriptions 

 are drafted from this material. 



Male. — Length 2.5 mm. Antennas probably extending to the 

 fourth abdoqiinal segment, sparsely haired, light yellow; 14 seg- 

 ments, the fifth binodose, the basal stem with a length one-half its 

 diameter, the distal with a length about three-fourths its diameter, 

 the basal enlargement subglobose, the distal subcylindric, slightly 

 expanded apically and with a length nearly twice its diameter; 

 three low, broad circumfili occur on each flagellate segment; ter- 

 minal segment irregularly binodose, with an indistinct constriction 

 near the basal third, the apex narrowly and irregularly rounded. 

 Mesonotum yellowish brown. Scutellum and postscutellum fus- 

 cous yellowish. Abdomen dark yellowish brown, the genitalia 

 fuscous yellowish. Wings hyaline, costa thickly haired, light 

 straw, the third vein uniting therewith well beyond the apex, the 

 fifth at the distal fourth, its branch near the basal half. Halteres, 

 coxae and femora basally yellowish, the distal portion of femora and 

 tibiffi dark brown, the tarsi a little lighter; claws slender, evenly 

 curved, simple, a little longer than the large pulvilli. Genitalia: 

 basal clasp segment short, broad; terminal clasp segment stout, 

 slightly curved and with a length thrice its diameter; dorsal plate 

 short, very broadly and roundly emarginate, the lobes strongly 

 divergent; ventral plate short, broadly rounded; style short, obtuse. 



Female. — Length 3.5 mm. Antennas nearly as long as the 

 body, sparsely haired, light yellow; 14 segments, .the fifth with r. 

 stem 34 the length of the cylindric basal enlargement, which latter 

 has a length 23^ times its diameter and three irregular, anastomos- 

 ing circumfili on the basal portion of the enlargement, with a fourth 



