FAM. MYCETOPHILID^ 
45 
17. Genus DIOMONUS, Walker 
Diomonus. Walker, List Dipt. Brit. Mus. Vol. i, p. 87 (1848). 
Characters. — This genus resembles Mycomya in wing venation, but differs in having three 
ocelli widely separated, the middle one but little smaller than the laterals (PI, I, Fig. 20 j. In the 
species with which I am familiar the basal joint of the antenna is densely pilose on the underside, the 
flagellar joints are somewhat flattened, especially toward the apex of the antenna (PI. I, Fig. 14), and 
the thorax is pilose rather than setose. The costa ends at or but very slightly beyond the tip of R^_|_5 close 
to the tip of the wing; the small cell Ri is less than twice as long as wide, the petiole of the media is 
much longer than the R-M crossvem ; the cubitus forks far proximad of the fork of media; the setute of 
the wing surface are longer and more dense than in Mycomya, and the wing has two dark spots upon 
it (PI. 4, Fig. 8). The legs are very long, the middle or hind femur of the male bears a blunt spme 
on the underside, and the male genitalia usually have two slender curved filaments (PI. 7, Fig. 4). 
The known species are 6-10 mm. in length. In other respects like Mycoinya. 
Type species : D. nebulosus, Walker. 
Geographical distribution of species : 
^ I. D. bifasciatiis, Say. Long's Exp. App. p. 363 (1824); Compl. Writ. Vol. i, United States, 
p. 246 [Sciophila) (1859). 
2. D. nebulosus. Walker, List Dipt. Brit. ^lus. Vol. i, p. 87 (1848). North America. 
^3. D. pulcher, Johannsen, Eint. News, Vol. 14, p. 14 (SciopJiila) (iqo3). Eastern United States. 
\4. D. stcbcaenilea, Coquillett, Proc. U.S.Nat. Mus. p. 5g5 {Sciophila) (igoi). Eastern United States. 
18. Genus MYCOMYA, Rondani 
Mycomya. Rondani, Dipt. Ital. Prodromus, Vol. i, p. 194 (5)(i855). 
Sciophila. Meigen (part.), Syst. Beschr. Vol. i, p. 246 (3o)(i8i8). 
? Sciobia. Loew, Ueber den Bernstein und Bernstein Fauna, p. 33 (i85o). 
Sciophila. Winnertz, Verb. Zool.-bot. Ges. Wien, Vol. i3, p. 707 (i863). 
Empheria. Winnertz, ibidem p. 73S(i863). 
Neoempheria. Osten Sacken, Cat. Dipt. North Amer. p. 9(1878). 
? Cnephaeophila. Philippi, Verb. Zool.-bot. Ges. Wien, Vol. i5, p. 618 (2) (i855). 
Characters. — The name Mycomya is used here in the sense of Sc/o/Z/Z/a of Winnertz over which 
it has priority, and includes also the genus N eoeinpJieria which can only be separated thus : 
a. Wings hyaline; costa not produced beyond R^^s Subgenus INIycomya, Rondani. 
aa. Wings banded ; costa usually produced Subgenus Neoeimpheria, Osten Sacken. 
Head small, flattened in front, placed low upon the thorax; eyes elongate oval or round; emar- 
ginate at the base of the antennae; ocelli two or three in number, placed close together upon a rounded, 
frequently blackened area (PI. I , Fig. 18), when three ocelli are present they are placed close together 
in a triangle, the median one very minute; proboscis very short; palpi incurved, four jointed, the first 
joint very small, the second somewhat longer, but shorter than the third, the fourth usually as long or 
longer than the three preceding taken together; face more or less wide; antennse projecting forward, 
arcuate, longer than the thorax in the male, subequal in the female, somewhat compressed, 2+i4jointed, 
the scape differentiated, the first two joints cupuliform, setose at the tip, the flagellar joints cylindrical 
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