388 



clear. The female has much the appearance of that of riparius but is 

 rather larger and more robust, the antennae are blackish, the abdomen 

 is almost entirely black, the segments having only very inconspic- 

 uous pale posterior margins, and the black color of the legs extends 

 more over the various joints. The male differs from chorens in hav- 

 ing the fore tarsi bare, and the proportions of basal joint and tibia 

 different. 



Length: male, 4-4.5 mm.; female, 3.5-4 mm. 



Type locality, South Haven, Mich., July 14, 1914. Taken by Mr. 

 Hart on shore of Lake Michigan. 



6. Protenthes BEEI.US Loew 



Tanypus hellus Loew, Berl. Ent. Zeitsehr., Vol. 10, 1866, p. 4. 



Larva. — Length, 5-6 mm. Yellow. Labial plate, apices of mandi- 

 bles, and claws of pseudopods brown, abdominal segments slightly 

 brownish on dorsum. 



Labial plate with the teeth similar to those of monilis, the lateral 

 basal process as in Protenthes culiciforniis; hypopharynx exposed as 

 in the latter species, 7-8 toothed ; mandibles as in monilis; antennae 

 short and rather thick, in length less than one third that of head and 

 about five times that of their basal diameter, the jointed apical por- 

 tion barely longer than the diameter of basal joint at apex, the apex of 

 the former with several short processes, the unjointed process on 

 apex of basal joint as long as the jointed portion and almost as thick ; 

 maxillary palpi short, barely more than twice as long as the diameter. 

 Claws of anterior pseudopods very numerous and much weaker than 

 those of the posterior pair, those of the latter unicolorous, mostly 

 slender, those of the subapical circle broader (PI. XXVI, Figs. 9, 

 10) ; dorsal tufts consisting of sixteen sensory hairs, the basal papil- 

 lae three times a long as thick. 



Pupa. — Length, 4-5 mm. Brownish yellow. Thoracic respiratory 

 organ as in Figure 9, Plate XXVH ; no distinguisiiable thoracic tu- 

 bercles. Abdomen without distinguishable hairs on dorsum, lateral 

 margins of penultimate segment with three long, slightly flatttened 

 hairs, last segment with five such hairs; apical appendages as in Figure 

 12, Plate XX VL 



Imago; Male and Female. — Pale rufous yellow, opaque. Head yel- 

 low, antennae pale brown, basal joint in male dark brown, in female 

 generally yellow, plumes of male antenna yellowish brown. Meso- 

 notum with the vittae pale reddish, rarely reddish brown ; scutellum 

 yellow ; postnotum the color of vittae. Abdomen yellow, all the seg- 



