6 
DIPTERA 
Type species: P. /rt^c/rt/a, Zetterstedt. 
Geographical distribution of species : 
I. P . fasciata, Zetterstedt, Ins. Lappon, Dipt. p. 85o (i838). Northern Europe. 
2. Genus THIRAS, Giebel 
Thiras. Giebel, Ins. d. Vorwelt, p. 235 (i856). 
Characters. — The fossil species upon which this genus is founded was first noted and figured 
by Westwood and was found in the Purbecks, England (Durdlestone Bay). As it is represented by 
only the wing its position in this subfamily is somewhat doubtful. The wing venation differs from all 
other members of the family in having a four branched radius, as in Pachyneiira, but having a simple 
media. The venation resembles somewhat that oi Mycelobia, in having a closed basal cell. The subcostal 
vein extends beyond the middle if the wing, its posterior branch is wanting, is distinct from R5 ; the 
media is simple, the two crossveins are about equidistant from the base of the wing; the ^nal veins well 
developed ( PI. 3, Fig. 5). 
Type species : T. Wesiivoodi, Giebel. 
Geographical distribution of species : 
I. T . Wesiwoodi, Giebel, Ins. d. Vorwelt, p. 235 (i856). — Figured by Westwood in Quarterly Journ. 
Geol. Soc. Lond. Vol, 10, p. 396, pi. 18, f, 20 (1S54). 
2. SUBFAM. B O L I TO P H I L I N >E 
Boiitophilinae. Vt^innertz, Verb. Zool.-bot. Ges. Wien, Vol. i3, p. 657 (i863). 
Characters. — Long slender species with elongate seven to nine segmented abdomen, twelve 
to seventeen jointed antennae, coxae either long or short; wings long and rather narrow; radius three 
branched, both the basal cells R and M distinct and closed at the distal end by the crossveins or by the 
coalescence of the basal section of the media and cubitus; the cell M much shorter than the cell R. 
TABLE OF GENERA 
a. shorter than the distance of its base from the crossvein, and shorter 
than R^j^s. 
b. Antennae seventeen jointed . slender {PI. 3, Fig. I) i. Genus Bolitophii-.a., Meigen. 
bb. Antennae twelve jointed {P\. 3, Fig. 2) 2. Genus IIesperinus, Walker. 
aa. R^j^j much longer than the distance of its base from tlie R-M cross- 
vein {P\. 3, Fig. 3) 3. Genus Mycetoph.etus, Scudder, 
I. Genus BOLITOPHILA, Meigen 
Dolitophila. Meigen, Syst. Beschr. Vol. i, p. 220 (1818). 
Messala. Curtis, Brit. Ent. p. 58i (i836). 
