ART. 8 FIVE NEW PARASITIC FLIES — J. M. ALDRICH 5 



Genus PEXOMYIA Brauer and Bergenstamm 



Pexomyia Brauer aud Bergenstamm, Zweifl. Kais. Mus., pt. 5, 1891, p. 329; 

 pt. 6, 1893, p. 114.— Brauer, Verb. Zool.-Bot. Ges., vol. 102, 1893, p. 476; 

 vol. 107, 1898, p. 543.— Baer, Die Tachinen, 1921, p. 78.— Stein, Arch. 

 Naturgesch., vol. 90, 1924, p. 99. 



The genus originally included Masicera rubrifrons Perris and 

 Roeselia aberrans Egger; the former was designated as type by 

 Brauer in 1893. and Bezzi, in the Palaearctic Katalog, makes the 

 latter a synonym. 



Two males of nibrifrons in the United States National Museum, 

 determined by Professor Bezzi, differ from Centeter in having bare 

 eyes and parafacials, the vibrissal axis somewhat longer, and the 

 prominent facial ridges with only weak bristles less than half-way up. 

 Discal bristles occur on the second and third segments, and a discal 

 row is present on the fourth. The habits of rubrifrons seem to be 

 unknown. 



The three related genera attacking ruteline beetles may be sepa- 

 rated by the following key. 



KEY TO CENTETER. STGELOTROXIS. AND PEXOMYIA 



1. The upper part of parafacial with distinct hairs anteriorly; eyes hairy. 



Centeter Aldrich. 

 Upper part of parafacial entirely bare; eyes bare 2. 



2. Facial ridges bristly to middle or above, discals absent on intermediate 



abdominal segments ; scutellum with no small apical pair of bristles. 



Sigelotroxis Aldrich. 

 Facial ridges bristly only below middle; discals present or absent; a small 

 pair of apical scutellars present between the large third lateral pair. 



Pexomyia Brauer and Bergenstamm. 



PEXOMYIA GENALIS, new species 



Femmle. — Front at vertex 0.41 of head width, parafrontal slightly 

 wider than median stripe, which is dark red and continues on each 

 side of ocellar triangle to inner vertical ; f rontals eight, extending to 

 tip of second antennal joint, upper two reclinate but not large; two 

 pairs of orbitals; parafacial wide; cheek equal to one-half the eye 

 height. Pollen of head decidedly yellow above, grayish-yellow on 

 parafacial, in front view the color changing suddenly below the 

 lowest frontal. 



Antennae reddish yellow nearly to middle of third antennal joint, 

 the remainder blackish ; the third joint four times the second. Arista 

 thickened and yellow almost one-half way; basal joints short; vi- 

 brissae at oral margin with six or seven small decreasing bristles 



