NO. I BLACK FLIES OF GUATEMALA — DALMAT 1 57 



spine. Body of adminiculum (pi. 23, fig. 44) semicircular, the apex 

 somewhat pointed, the base with slight concavity; entire ventral sur- 

 face clothed with short and long hairs, the longer ones closer to apex ; 

 basal processes short, well sclerotized, pointed. Adminicular arms 

 (pi. 23, fig. 45) with about 20 teeth arranged along distal half of arm, 

 more numerous near apex ; lateral plate narrow, somewhat quad- 

 rangular in shape. 



Female (pi. 30, figs. 160-162, and pi. 35, fig. 266). — 2.5 mm. 



Head : Dichoptic. Eyes reddish brown with gray pruinosity ; base 

 of fronto-ocular triangle 1.8 times the height. Antenna 500 /a long, 

 1 1 -segmented, slightly tapering beyond segment 5 ; segment 3<i-t-2, 

 3<4-|-5, 3=11; scape and pedicel yellow, flagellum dark brown. 

 Palpi brown, with gray pruinosity. Frons coppery red with gray 

 pruinosity and with dark-brown hairs. Clypeus coppery red with 

 silvery scales near its midregion. Occipital region coppery red with 

 long yellow hairs along entire periphery. 



Thorax : Mesonotum very dark reddish brown ; 2 longitudinal 

 bands of white pruinosity, wider at the anterior margin, where they 

 originate, extending to prescutellar region which is also white- 

 pruinose ; lateral margins also white-pruinose ; the longitudinal bands 

 divide the mesonotum into 3 reddish-brown vittae ; short, narrow, 

 yellow, scalelike hairs over entire surface of mesonotum, somewhat 

 longer in prescutellar region ; short black hairs over entire mesonotum. 

 Humeral angles very dark reddish brown with white pruinosity. 

 Scutellum light yellow, with white pruinosity, and with long black 

 hairs and golden scalelike hairs. Postnotum reddish brown, gray- 

 pruinose, devoid of hairs. Pleura reddish brown with white pruinosity. 

 Stem of halter brown, the knob white. Wings, 2.9 mm. long and 

 1.3 mm. wide ; relation of body length to wing, i : 1.2 ; Sc pilose along 

 its basal three-fifths ; Ri with both spines and hairs along distal half ; 

 R2+3 pilose except for very small basal section ; Cu2 arcuate ; discal 

 cell absent. 



Legs : Leg i, length, 2.9 mm. ; coxa, trochanter, and femur yellow ; 

 tibia yellow with dark apical ring ; tarsus reddish brown. Leg 2, 

 length, 2.5 mm. ; coxa reddish brown ; trochanter yellow ; femur yellow 

 with dark apical ring; basal half of tibia and basitarsus yellow, the 

 apical half brown; tarsal segments 2-5 dark brown. Leg 3, length, 

 3.2 mm. ; coxa dark reddish brown ; trochanter yellow ; femur yellow 

 on basal fourth, dark brown on apical three-fourths, with numerous 

 black hairs ; tibia yellow on basal half, dark brown on apical half ; basal 

 three-fifths of basitarsus and basal half of second segment yellow, the 

 remainder of these segments, as well as all of segments 3-5, dark 



