NO. I BLACK FLIES OF GUATEMALA — DALMAT IO9 



Pleura brown, slightly gray-pruinose, the pre-alar cluster composed 

 of yellow hairs. Halter with brown stem, darker at base, the knob 

 brown, infuscate, and very large. Wings, 4.0 mm. long and 1.7 mnx 

 wide; relation of body length to wing, 1:1.1; So pilose along basal 

 four-fifths ; Ri completely pilose, also with a few spines along distal 

 third ; R2+3 pilose except for small basal region, at times with a single 

 basal hair ; Cu2 straight ; discal cell absent. 



Legs: Leg i, length, 3.2 mm.; coxa and trochanter dark brown; 

 femur brown, with very small apical dark ring ; tibia light brown 

 except for basal and apical dark rings and dark band along one mar- 

 gin ; tarsus light brown. Leg 2, length, 3.0 mm. ; coxa dark brown ; 

 trochanter light brown ; femur light brown with dark-brown apical 

 ring ; tibia light brown with wide basal and apical dark rings ; tarsus 

 light brown. Leg 3, length, 4.0 mm. ; coxa dark brown ; trochanter 

 light brown ; femur light brown with very wide, dark apical ring ; 

 tibia light brown with basal and apical fourths almost black ; basitarsus 

 and second segment light brown, the other tarsal segments dark 

 brown ; relation of basitarsus to second tarsal segment, 7.4 : i ; calcipala 

 very large, covering about two-thirds of second tarsal segment ; pedi- 

 sulcus absent, represented by slight indentation ; claw with well- 

 developed heel and with a secondary toothlike structure that emerges 

 at the base, this structure being somewhat quadrangular, one of its 

 apical angles prolonged (pi. 35, fig. 273). 



Abdomen : Tergite i light brown, clothed with short yellow hairs ; 

 pleurites light brown with long yellow hairs that reach the third seg- 

 ment. Segment 2 brown on anterior half and dark brown on posterior 

 half ; somewhat gray-pruinose ; with short yellow hairs. Other seg- 

 ments dark brown, with narrow light-brown band along posterior 

 margin, covered with short yellow hairs. Stemites tan. 



Genitalia : Cercus (pi. 28, fig, 130) rectangular in shape, the 

 height slightly more than twice the length (width). Anal lobe (pi. 28, 

 fig. 130) almost semicircular in shape, the dorsal extremity somewhat 

 tapered, the ventral greatly expanded and extending under the cercus. 

 Genital rod (pi. 28, fig. 132) with well-developed basal dilatation that 

 is oval in shape ; rod rather short ; apical expansions of genital fork 

 hyaline, very clear, like a broad, subquadrangular membrane, the outer 

 apical angle prolonged into narrow structure that recurves toward the 

 base ; inner apical angle expanded into truncate structure. Ovipositor 

 (pi. 28, fig. 131) triangular in form, small. 



Pupa (pi. 36, fig. 280, and pi. 39, fig. 320). — Granulosity on entire 

 thorax ; 5 simple trichomes on either side of midline of thorax. Dorsal 

 surface of abdominal segments : Granulosity over dorsum of all seg- 



