NO. I BLACK FLIES OF GUATEMALA — DALMAT 25 1 



knob yellow, elongate. Wings, 3.9 mm. long and 1.4 mm. wide; rela- 

 tion of length of body to wing, i : 1.3 ; Sc pilose along basal two-thirds ; 

 Ri pilose and spiny along distal half ; R2+3 pilose along distal four- 

 fifths ; Cu2 arcuate ; discal cell absent. 



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

 femur dark brown, its basal third somewhat lighter than the apical 

 two-thirds ; basal three-fourths of tibia yellow, apical fourth black ; 

 tarsus black. Leg 2, length, 2.9 mm. ; coxa and trochanter brown ; 

 femur brown with apical black ring; tibia yellow on the basal three- 

 fourths, black on apical fourth ; basal half of basitarsus yellow, apical 

 half black ; tarsal segments 2-5 black. Leg 3, length, 3.7 mm. ; coxa 

 dark brown, trochanter light brown ; femur brown with apical black 

 ring; tibia with basal half yellow, middle fourth brown, and apical 

 fourth black; basal halves of basitarsus and second segment yellow, 

 the apical halves of these segments, as well as all of segments 3-5, 

 black; relation of basitarsus to second tarsal segment, 5.1:1; cal- 

 cipala well developed, reaching only halfway to pedisulcus ; pedisulcus 

 well developed at middle of second segment ; claw with basal heel well 

 developed and with submedian tooth (pi. 35, fig. 253). 



Abdomen : Tergite of segment i black ; pleurites black with long 

 dark hairs reaching third segment. Segment 2 black, the tergite white- 

 pruinose. Other segments black, the pleurites somewhat white-prui- 

 nose ; few long black hairs on last segment. Sternites tan. 



Genitalia: Cercus (pi. 33, fig. 220) rectangular, its height 1.5 

 times its length (width), clothed with some long, strong hairs and 

 with numerous minute spinelike hairs. Anal lobe (pi. 33, fig. 220) 

 somewhat crescent-shaped, curving around the ventral margin of the 

 cercus. Genital rod (pi. 34, fig. 222) with slight basal dilatation ; 

 apical expansions of arms of genital fork triangular in shape, hyaline ; 

 the outer basal angle somewhat pointed, the others blunt. Ovipositor 

 (pi. 33, fig. 221) somewhat triangular in shape, the apex rounded, its 

 height equal to the base. 



Pupa (pi. 38, fig. 310, and pi. 39, fig. 350). — Granulosity on entire 

 thorax; 6 short, simple, stout, spinelike trichomes on either side of 

 midline. Dorsal surface of abdominal segments : Segment i with 

 granulosity along middle of posterior margin ; spines on segments 2-4 

 are anteriorly directed, those on segments 6-9 are posteriorly directed ; 

 segment 2 with 8 simple spines in a transverse row crossing the seg- 

 ment three-fourths the distance from the anterior margin, the row 

 being divided into two by a median space ; outermost spine on either 

 side more distant from the neighboring spine than the distance between 

 any other two ; anterior to the outermost spine on either end of the 



