431 



Pupa. — Length, 8-9 mm. Dark brown. Frons without tubercles. 

 Thoracic respiratory organs hairHke, of the usual chironomid type. 

 Second abdominal segment with the normal apical transverse series 

 of setulse, the other segments without distinct setulse ; segments 2-6 

 with a macelike flattened process lying close to dorsum, which appar- 

 ently projects from the apex of the preceding segment and is armed 

 apically with spines (see PI. XXXI, Fig. 2) ; apical lateral comb of 

 eighth segment very short, consisting of about seven teeth ; apical ap- 

 pendage with the normal fringe. 



Imago; Male. — Brownish black. Head and its members black, 

 antennal plumes dark brown. Thorax covered with grayish prui- 

 nescence, the black vittae less densely covered than the spaces between. 

 Abdomen black, posterior half of each segment with a large gray pru- 

 inose spot on each side, the spots meeting in center posteriorly. Legs 

 yellow, apices of femora and bases of tibiae generally distinctly brown- 

 ish, apices of tibiae and of tarsal joints narrowly brown. Wings 

 slightly grayish, veins brown, cross vein slightly infuscated. Halteres 

 yellow. 



Pronotum broad, nearly equal in width to apex when viewed from 

 side, not extending to upper margin of mesonotum. Abdominal seg- 

 ments with bare depressions on the areas, corresponding to those of 

 pupa, which underlie the macelike projections ; segments 6 and 7 

 slightly broader and shorter than 5 ; hypopygium as in Figure 9, Plate 

 XXXin. Fore tarsus with long hairs on posterior surface from 

 middle of basal joint, the latter more than one and a half times as 

 long as fore tibia. Cubitus forking almost directly below cross vein. 



Female. — Agrees with male in color, and in the structure of ab- 

 domen — aside from the genitalia. Fore tarsi without the long hairs. 



Illinois localities : Havana and at various other points on the 

 Illinois River as far north as IMarseilles, above the dam — larvae, pupae, 

 and imagines; Muncie, Champaign. L^rbana, Dubois, East St. Louis, 

 — on dates ranging from April 24 to September 6. Some specimens 

 were taken at light. 



Originally described by Say, who said in regard to its distribution : 

 "Inhabits the L^nited States." Johannsen records its occurrence at 

 Albany, N. Y., in the larval stage, and described the dorsal abdominal 

 appendages of the pupa, though he indicated that they were imaginal 

 and not pupal. The same, as to description, is true of Say. My 

 miscroscopic preparations prove that the appendages they described 

 were pupal, as described herewith. I have before me examples of this 

 species from Lake Delavan, Wis., and from Berrien Springs and 

 Grand Junction, Mich., taken by Mr. Hart; and have seen examples 

 from Plummer's Island, Md. (W. L. McAtee). 



