NO. I BLACK FLIES OF GUATEMALA DALMAT II3 



brown. Leg 2, length, 1.7 mm. ; coxa dark brown; trochanter, femur, 

 tibia, and tarsus light brown. Leg 3, length, 2.0 mm. ; coxa dark 

 brown ; trochanter light brown ; basal two-thirds of femur light brown, 

 the apical third dark brown ; tibia with basal half light brown, the 

 apical half dark brown ; basitarsus light brown with dark brown an- 

 terior edge ; tarsal segments 2 and 3 light brown, 4 and 5 dark brown ; 

 relation of basitarsus to second tarsal segment, 5.3 : i ; calcipala well 

 developed but not quite reaching the pedisulcus ; pedisulcus well 

 formed at middle of second tarsal segment. 



Abdomen : Tergite of segment i dark brown to black, with short 

 black hairs ; pleurites of same color, with long black hairs that reach 

 segment 4. Segment 2 dark brown to black, the anterior half and 

 pleural regions white-pruinose, with short black hairs. All other seg- 

 ments dark brown to black, the pleural regions shiny white-pruinose, 

 with short black hairs. Sternites brown, with gray pruinosity. 



Genitalia : Sidepiece (pi. 22, fig. 18) wider than long, quadrangu- 

 lar in shape, with dorsal concavity near middle of apical margin ; 

 dorsal opening occupying about three-fourths of dorsal surface of 

 sidepiece. Clasper (pi. 22, fig. 18) about half the length of sidepiece, 

 conical in form, almost dome-shaped, the apex blunt and rounded, 

 without terminal spine; basal aperture extending along at least one- 

 half the length of clasper. Body of adminiculum (pi. 22, fig. 17) 

 roughly triangular in shape, the apical angle rounded ; basal margin 

 broadly arched ; minute spinelike hairs on ventral surface ; basal proc- 

 esses short, well sclerotized, somewhat convergent, and blunt. Arms 

 of adminiculum (pi. 22, fig. 16) with several teeth, somewhat concen- 

 trated near the apex ; one long, broad tooth at the apex, directed in the 

 opposite direction from the others ; lateral plate narrow, with several 

 wrinkles. 



Female (pi. 28, figs. 133-135, and pi. 35, fig. 274). — 1.8 mm. long. 



Head : Dichoptic. Eyes black ; no fronto-ocular triangle. Antenna 

 370 /A long, 1 1 -segmented, very slightly tapering; segment 3<i+2, 

 3<4 + 5, 3=11 ; scape and pedicel light brown, the flagellum black; 

 the first two or three flagellar segments are also light brown at times. 

 Palpi brown. Frons, clypeus, and occipital region black, bluish-white- 

 pruinose, irregularly clothed with short black hairs. Cornuae of bucco- 

 pharyngeal apparatus heavily sclerotized, tapering, the apex blunt ; 

 median space hyaline, broad. 



Thorax : Mesonotum black, completely gray-pruinose, without 

 longitudinal bands, stripes, or other designs; short, narrow, yellow, 

 lustrous, scalelike hairs over entire mesonotum, denser along the 

 periphery, arranged in packets ; in prescutellar region these hairs are 



