8 
DIPTERA 
small, round; proboscis short, palpi long, incurved, four segmented; antennas rather long, twelve 
jointed, the basal joints small, the flagellar joints elongated, flattened, the terminal joints strongly 
constricted beyond the middle, the apical joint very small, oval; eyes round; three ocelli. Mesonotum 
arched, no transverse suture, somewhat depressed before the scutellum, which is small, metanotum 
prominent though but slightly arched. Abdomen long and slender, seven or eight segmented, somewhat 
enlarged toward the caudal end in the male, and with prominent genitalia. Legs long and slender; 
coxae not elongate; femora somewhat thickened distally; tibiae with small spurs; metatarsi lengthened, 
claws small, pulvilli distinct, empodium well developed; halteres free. Wings lar e and broad; Scr 
long, extending beyond the middle of the wing; R2+;, shorter than the distance of its base from the 
R-M crossvein, the media rises at the base of the wing, the fork of the cubitus and the M-Cu crossvein 
equidistant from the base of the wing and far proximad of the R-iM crossvein (PI. 3, Fig. 2). The 
immature stages unknown. 
Type species : H . brevifrons, Walker. 
Geographical distribution of species : 
1. H. brevifrons. Walker. List Dipt. Brit. Mus. Vol. i, p. 81 (1848). North America. 
2. H. conjungens, Schiner, Novara Raise. Dipt. p. 23 ( 18) (1868). Brazil. 
3. H. imbecilhis, Loew, Berl. Ent. Zeitschr. \'ol. 2, p. 108, pi. i, f. 5-9 Central Europe. 
{Spodius) (i858). 
imbecillus, Mik, Verh. Zool.-bot Ges. Wien, Vol. 14, p. 798 iSpodius) 
(1864); Schiner, Fauna Austr. Dipt. Vol. 2, p. 640 [Spodius) (1864). 
3. Genus MYCETOPH/ETUS, Scudder 
Mycetophaetus. Scudder, Bui. U. S. Geol. Survey, No. 93, p. 19 (1892). 
Characters. — This fossil genus appears to be closely akin to Hesperinus, differing mainly in 
having a much longer R24-3. The Scj extends beyond the middle of the wing; the vein R2+3 arises 
a little beyond the R-M crossvein and ends in the costa ; the costa is prolonged to near the tip of the 
wing where it meets R4+5; the media arises at the base of the wing; the cubitus forks slightly proxi- 
mad of the M-Cu crossvein and far before the R-M crossvein ; the anal vein is produced to the margin 
of the wing. Legs long and slender, the fore femora considerably longer than the thorax, the tibia 
longer than the femora, both abundanth' spinose. Abdomen eight segmented (PI. 3, Fig. 3). 
Type species : M. interwedius, Scudder. 
Geographical distribution oFspecies : 
I. M. intermedins, Scudder, Bull. U. S. (ieol. Survey, No. g3, p. 20(1892). Florissant, Colorado, U. S. 
3. SUBFAM. M YC ETO B I I N >E 
Mycetobiinse. Winnertz, Verh. Zool.-bot. Ges. Wien, Vol. i3, p. 665 (i863). 
Characters. — A group possessing in common the following characters : i5 or 17 jointed 
antennae; three ocelli on the vertex; wings rather broad, both the R-M and the M-Cu crossveins pre- 
sent and nearly equidistant from the base of the wing ; radius three branched; legs long and slender 
and the tibial spurs rather short. 
