120 Bulletin Wisconsin Natural History Society [Vol. 13, No. 2 
The lateral carina is very distinct in the pupae, nearly straight in each 
segment and ends posteriorly with a thick black tooth. Each segment 
except the first with a pair of marginal setae on the carina slightly before 
the middle of the segment, another seta terminally above the tooth; in 
the last segment all three setae are subterminal. 
Last segment ventrally and laterally much wrinkled, dorsally with 
appendages, apically each side three filaments shorter than the last 
segment. 
Professor JohannseiTs description of the pupa is not sufficiently 
detailed to permit a comparison with D. waltlii. As far as the 
description goes the present species is practically identical in 
the pupal stage. Thalassomyia obscura is stated by Johannsen 
to have “a transverse band of stout black bristles. Each band 
is composed of five or six rows. . . . The anal segment is 
composed of two small lobes, each with a single apical bristle.” 
This combination of larval characters of Thalassomyia and of 
pupal characters of Diamesa is of interest in the present species. 
The pupal stages of Thalassomyia and Diamesa mendotae have 
little in common, notwithstanding the remarkable affinities of 
the larvae (assuming, of course that the larvae are properly 
assigned. See remarks under “larva”). Diamesa mendotae 
(and also D. waltlii Meigen and D. insignipes Kieffer) has only a 
single caudal row of spines on each abdominal segment of the 
pupa, while T. obscura has several rows. The number of anal 
filaments is reduced to one in Thalassomyia , while three or more 
are present in all known pupae of Diamesa. 
THE IMAGO 
d”. — Color black. Head and eyes black, antennae and antennal hairs 
brown. Antennae with fourteen joints, the first joint large, the second 
as broad as long, the following nine shorter than their width, the next two 
as long as wide, the last twice the length of the others combined, ciliated 
with shortening cilia till near the tip, which has only a very few cilia dis- 
tributed between the sense pits. Palpi four-jointed, the basal joint small 
and not well marked off from the following joint, about as long as broad; 
second joint three times the length of the first, swollen; third joint cylin- 
drical, as long or very little longer than the second; the fourth joint cylin- 
drical, thinner than the third, and about one-fifth or one-fourth longer. 
Thorax black, faintly glossy, with a faint and very narrow light line 
on the metanotum; pleura and scutellum black. Legs pale fuscous or light 
brown, all the joints annulate with black distally. Wings broad, reach- 
ing to the tip of the seventh segment, anterior venation brown to black. 
