342 THE BLOWFLIES OF NortH AMERICA 
4. Middle tibia with ventral bristles; hind tibia with antero- 
ventral: bristlessosat : wieie Auten 8. eee) OF Se 5) 
Middle and hind tibiae without ventral or anteroventral 
bristles (Nearctic) ...3........0 70 02 a 
ER ITC IET. 2018 Melanodexiopsis tristina, new species, p. 359 
9. Lwo’postacrostichal bristles. ..)... "0... <4... +n ee 6 
Only one postacrostichal bristle (Nearctic).............. 
ng tae .. .Melanodexiopsis pacifica, new species, p. 399 
6. Frontal bristles in one row (Nearctic) ee 
Bs ocd a tae Melanodexiopsis nox, new species, p. 358 
Frontal bristles in two rows (Nearctic)...............0- 
3 Stet. martes. Melanodexiopsis grandis (Shannon), p. 357 
7. Two or more postacrostichal bristles................... 8 
Only one postacrostichal bristle (Nearctic)............... 
fy ee Ee ees Melanodexia glabricula (Bigot), p. 354 
8. Two postacrostichal bristles (Nearctic)... Od eee 
PER ne Ree hat Re Melanodexia satanica Shannon, p. 355 
Three postacrostichal bristles (Nearctic)................. 
ONE Ue TSE Melanodea californica, new species, p. 354 
TRIBE POLLENIINI 
Only one genus and one species belonging to this tribe occur 
in North America. 
Male and female. Head with palpus half as long as head at 
antenna, thick, clavate; antennal bases narrowly separated; third 
antennal segment twice as long as second, reaching four-fifths 
the distance to the vibrissa; arista thickened one-third the dis- 
tanee to the apex, with cilia to apex. Thorax, abdomen, and 
eoxae usually with thick, yellowish or tawny, crinkly pile or 
hair; hindmost preintraalar bristle present and placed close to 
suture; posthumeral bristle present. Wing with only third vein 
provided with setulae and these at base; anterior cross vein 
before the middle of the second section of fourth vein in the 
proportion 8:7; last section of fifth vein one-fourth as long as 
preceding section; both squamal lobes entirely bare on disc. 
POLLENIA ROBINEAU-DESVOIDY 
Pollenia Robineau-Desvoidy, Essai sur les Myodaires, Paris, p. 
412, 1880; Schiner, Fauna Austriaca, Die Fliegen, vol. 1, p. 
585, 1862; Brauer and Bergenstamm, Zweifltigler des Kaiser- 
lichen Museums zu Wien, vol. 4(1), p. 87, 1889; ibid., vol. 
