Aquatic Insects of Michigan
by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
Pseudochironomus richardsoni Malloch, 1915
Diagnosis: Male imago characterized by having about 60 dorsocentrals in 3-6 rows; thorax and abdomen almost uniformly blackish; AR 1.7-2.6; LR1 0.84-0.94; HR about 1.6; about 8-9 snesilla chaetica on each ta1 of p2 and p3; Ab9 tergite with apical notch; pars ventralis small and completely divided. Pupa is characterized with having only about 15 filamentous setae confined to the caudal half in the fringe of the anal lobe. The larva has an AR of about 1.7, the basal antennal segment about 120 Ám long, and Ant3 0.6x as long as Ant2.
Thorax: Antepronotum with 6 setae. Dorsocentrals 59 in 3-6 rows, prealars 10, parascutellars 1. Scutellum with 22 setae in 2 or 3 rows. Wing. VR 1.9. Brachiolum with 3 setae, R with 15 setae, R1 with 1 seta, R4+5 with 1 seta. Squama with 39 setae. Legs. Spur of front tibia 78 Ám long; spurs of middle tibia 78 Ám and 65 Ám long; of hind tibia 89 Ám and 74 Ám long. Width of apex of front tibia 66 Ám; of middle tibia 71 Ám; of hind tibia 74 Ám. Sensilla chaetica 8 or 9 on ta1, of each p2 and p3. Lengths (Ám) and proportions of legs: