448 



fuscous, the plumes brownish yellow ; palpi brown. Mesonotum 

 opaque, the vittae gray, spaces between the latter with slight grayish 

 pruinescence ; sternopleura except the upper margin, a large spot in 

 front of wing-base, and another in front of posterior spiracle, black- 

 ish ; scutellum yellow ; postnotum blackish gray. Abdominal segments 

 broadly blackish brown on bases, leaving only the apical third of the 

 basal four yellowish and only a narrow yellow apical margin to the 

 others. Legs yellow, knees and apices of tarsal joints slightly ob- 

 scured with brown. Wings clear, cross vein distinctly infuscated. 

 Halteres yellow. Hairs on legs and body yellow. 



Frontal tubercles of moderate size ; apical joint of palpi longest, pro- 

 portions of apical three joints, 22, 15, 15. Pronotum rather broad, cen- 

 tral division, seen from above, wedge-shaped. Hypopygium similar to 

 that of ferrugineovittatus (see PI. XXXIII, Fig. 4), but the superior 

 processes are slightly broader in comparison with their length, and the 

 apical portion of the lateral arm is as shown in Figure 17, Plate 

 XXXIV. Legs slender ; fore tarsi with long hairs on posterior surface 

 from middle of basal joint to near apex of third, proportions of tibia 

 and basal three fore-tarsal joints, 98, 122, 63, 38; mid and hind legs 

 with long hairs. Third vein ending as far before apex of wing as 

 fourth does behind it ; cubitus forking very slightly beyond cross vein. 

 Female. — In color similar to the male except that the legs have the 

 apices of the joints, including the tibiae, distinctly marked with brown, 

 and the hind femora are usually darkened above on the apical half, and 

 the bases of the fore femora are often slightly brownish. 



Structurally it differs from the male in having the antennae short, 

 consisting of the usual 8 joints, and with short hairs, the body stouter, 

 the legs with shorter hairs, and no long hairs on the fore tarsi. 



Length, 12 mm. 



Illinois localities: Urbana, April 11, and Champaign, July 21, 

 1887. the former at light (C. A. Hart). 



This species was originally described from Europe, where it occurs 

 in almost every place where there are small boggy pools. It has been 

 recorded in North America from Mackenzie River in Canada, Chau- 

 tauqua Lake and Ithaca, N. Y., and from Washington State. I have 

 before me specimens taken at Lake Delavan, Wis., and Grand Junc- 

 tion, Mich., in September and July respectively, by Mr. Hart. 



Johannsen was mistaken in supposing that the larva mentioned by 

 Garman as "No. 4"* might be of this species. Although there are no 

 reared specimens of the species at hand, the fact that pluuiosus does 



*Bull. Til. State Lab. Nat. Hist., Vol. 3, Art. 9, p. 160 (158, sec. ed.). 1888. 



