NO. I BLACK FLIES OF GUATEMALA — DALMAT 221 



brown with long black hairs. Postnotum dark reddish brown, white- 

 pruinose. Pleura dark brown, with white pruinosity. Stem of halter 

 dark brown, the knob yellow. Wings, 2.2 mm. long and i.i mm. wide ; 

 relation of body length to wing, 1.2 : i ; Sc pilose along basal eighth ; 

 Ri spiny along distal half (no hairs) ; R2+3 pilose except for very 

 short basal section ; Cu2 arcuate ; discal cell absent. 



Legs: Leg i, length, 2.3 mm.; coxa and trochanter light brown; 

 femur light brown with dark-brown apical ring ; tibia with apical and 

 basal fourths dark brown, the median half light brown ; tarsus black. 

 Leg 2, length, 2.0 mm. ; coxa, trochanter, femur, and tibia dark brown ; 

 basal three-fourths of basitarsus and basal two-thirds of second tarsal 

 segment light brown, the remainder of these segments, as well as all 

 of segments 3-5, dark brown to black. Leg 3, length, 2.5 mm. ; coxa 

 black; trochanter, femur, and tibia dark brown; basal half of basi- 

 tarsus and of second segment light brown, the apical halves of these 

 segments, as well as all of segments 3-5, black ; relation of basitarsus 

 to second segment, 5.1 : i ; calcipala well developed, reaching the 

 pedisulcus ; pedisulcus well formed at middle of second segment. 



Abdomen : Tergite of segment i dark brown with short black 

 hairs ; pleurites black with long black hairs that reach segment 5. Seg- 

 ment 2 dark brown, the anterior half of the tergum and all of pleurites 

 white-pruinose, with short black hairs. All other segments dark 

 brown, the anterior half of pleural regions of segments 5-7 white- 

 pruinose ; all segments with short black hairs, segment 3 with a con- 

 centration of them. Sternites white-pruinose. 



Genitalia: Sidepiece (pi. 25, fig. 82) somewhat wider than long; 

 apical margin narrower than base, with inner apical angle somewhat 

 prolonged on ventral surface ; dorsal opening occupying about three- 

 fourths of dorsal surface of sidepiece. Clasper (pi. 25, fig. 82) about 

 three and one-half times longer than it is wide, tapering slightly from 

 base to apex ; with basal extension on dorsal surface, directed laterally, 

 wedge-shaped, slightly longer than its base; i terminal spine. Body 

 of adminiculum (pi. 25, fig. 84) in form of narrow cone-shaped struc- 

 ture, the apex quite acute ; with longitudinal wrinkles ; basal processes 

 very long, broad, well sclerotized, their apices spatulate ; darkly pig- 

 mented ribbonlike structure passing along the basal region of the body 

 of adminiculum and appearing to enter each of the basal processes ; 

 triangular-shaped, membranous, winglike expansion on either side, 

 extending from basal third of body to near the end of basal processes. 

 Arms of adminiculum (pi. 25, fig. 83) with about 10 teeth, two apical 

 ones which are long, the others short and blunt ; lateral plate triangular 

 in shape, wrinkled. 



