NO. I BLACK FLIES OF GUATEMALA — DALMAT I4I 



pruinosity. Stem of halter yellow to brown, the knob white. Wings, 

 1.9 mm. long and 0.94 mm. wide; relation of body length to wing, 

 I : I ; Sc pilose along basal sixth (3 hairs) ; Ri spiny and pilose along 

 distal half ; R2+3 pilose along distal four-fifths ; Cu2 arcuate ; discal 

 cell absent. 



Legs: Leg i, length, 2.1 mm.; coxa light brown; trochanter and 

 femur yellow ; tibia yellow on basal half, black on apical half ; tarsus 

 black. Leg 2, length, 1.8 mm.; coxa black; trochanter and femur 

 yellow ; tibia yellow on basal half, brown on apical half ; basitarsus 

 yellow with brown apex ; tarsal segments 2 and 3 yellow on basal half, 

 brown on apical half ; segments 4 and 5 dark brown. Leg 3, length, 

 2.2 mm. ; coxa black ; trochanter yellow ; femur black except for small 

 basal area that is dark brown ; tibia yellow on basal two-fifths, black 

 on apical three-fifths ; basal two-thirds of basitarsus and basal half of 

 second segment yellow, the apical portions of these segments, as well 

 as all of tarsal segments 3-5, black ; relation of basitarsus to second 

 segment, 4.1 : i ; calcipala well developed, reaching halfway to pedi- 

 sulcus ; pedisulcus well developed at middle of second segment. 



Abdomen : Tergite of segment i black with short black hairs ; 

 pleurites black with long black hairs reaching the fourth segment. 

 Segment 2 velvety black with white pruinosity on the pleural regions 

 and with short black hairs. Other segments velvety black ; segment 5 

 with white pruinosity on pleurites and segment 6 having it both on 

 tergite and pleurites ; all segments with short black hairs. Sternites tan. 



Genitalia: Sidepiece (pi. 23, fig. 34) somewhat conical in shape, 

 longer than wide ; apical end shorter than base ; dorsal opening occu- 

 pying less than half of dorsal surface of sidepiece. Clasper (pi. 23, 

 fig. 34) almost rectangular in shape, the inner apical angle extended 

 to form a prolongation at the tip of which there is a single terminal 

 spine. Body of adminiculum (pi. 23, fig. 36) triangular, the apical end 

 sharply extended, its apex rounded ; ventral surface covered with nu- 

 merous hairs ; basal processes short, at definite angle to the body of 

 adminiculum, well sclerotized, pointed, with slight posteriorly directed 

 spur on lateral margin of each. Arms of adminiculum (pi. 23, fig. 35) 

 with about 12 teeth, five of which are sharply pointed and form a 

 domelike apex, the others distributed along the rest of the arm ; lateral 

 plate rectangular, slender. 



Female (pi. 29, figs. 1 51-153). — 1.9 mm. long. 



Head : Dichoptic. Eyes dark reddish brown ; fronto-ocular triangle 

 small, the base 1.6 times the height. Antenna 410 fi long, ii-seg- 

 mented, broad, slightly tapering; segment 3<i+2, 3<4-f-5, 3=ii; 

 scape, pedicel, and first flagellar segment yellowish, the remainder 



