280 Mr. C. H. T. Townsend on Diptera 
varies from reddish yellow to black. It is black in nearly 
all of the females, while in most of the males it is lighter. 
The females are all quite constant in being without the 
postsutural golden markings of mesoscutum, or with only a 
trace of them. These markings consist in these forms of 
three golden lines joined posteriorly by a transverse line. 
They are constant and well defined in all of the males. The 
males vary in wing-colouring from specimens having a large 
yellow patch extending along costal margin from base of 
wing two-thirds way to tip, to others in which the yellow is 
subobsolete or entirely wanting; while the females, though 
usually without aay yellow, in several cases show a trace of 
it on the wings. ‘The femora in all the specimens are more 
or less broadly yellowish at base. Palpi reddish yellow. 
The orbital margins in all the females are silvery pollinose, 
in the males golden pollinose. The claws of both sexes, 
especially the female, vary in length, but they are usually 
comparatively longer in the male. The female abdomen is 
usually narrowed at tip. The abdomen of all the males is 
distinctly truncate apically, usually more or less flattened, 
and rarely subcylindrical. But in this connexion the male 
taken June 18 deserves special mention. It has the elongate 
tapering subcylindric abdomen of the female, is entirely 
without yellow on the wings, and has the postsutural golden 
markings less distinct; but it has the claws characteristic of 
the male, and possesses the male hypopygium. ‘This differ- 
ence in shape of the abdomen may be abnormal in this 
specimen. Another male, with well-marked yellow on the 
wings, approaches it somewhat in this respect. 
Typical var. pennipes, Fabr.—The specimens of the above 
which I refer here are as follows: Thirteen males, one each, 
March 9, June 30, July 1, 2, 3, and 17; two each, July 4 
and 5; and three, July 6. Two females, July 4 and 18. 
Length 63 to 10 millim. 
Characterized by having a more or less distinct patch of 
yellow on wings in both sexes, less distinct in the female. 
Scutellum generally lighter in coloration. Wings appearing 
less pronouncedly black. Abdomen rust-yellowish. 
Var. pilipes, Fabr.—The specimens which I would refer 
here are: Three males, June 18 (the ones specially mentioned 
above), July 4 and 10; six females, all July 3, except one 
July 2. 
Length 7 to 11 millim. 
Characterized by having no yellow on wings in either sex, 
or hardly a trace in the male. Scutellum generally shining 
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