NO. I BLACK FLIES OF GUATEMALA — DALMAT 215 



shiny, with single row of black hairs on proximal and lateral margins. 

 Clypeus dark brown, white-pruinose, with a few tan hairs on lateral 

 margins. Occipital region black, covered with short tan hairs. Cor- 

 nuae of buccopharyngeal apparatus sclerotized, wide, the ends shovel- 

 like ; median space hyaline, smooth. 



Thorax: Mesonotum velvety black; band of silvery pruinosity 

 around entire scutum, the posterior third to fourth of scutum com- 

 pletely pruinose ; 3 longitudinal bands of white pruinosity extending 

 from the white pruinosity along the anterior margin to that at the 

 posterior margin, the central band located along the midline, the others 

 being on either side of it ; short black hairs over entire mesonotum, 

 long ones in present ellar region. Humeral angles black, with white 

 pruinosity. Scutellum brown to black, with some long black hairs. 

 Postnotum brown to black, the anterior half white-pruinose. Pleura 

 dark brown, with white pruinosity. Stem of halter dark brown, the 

 knob yellow. Wings, 2.9 mm. long and 1.3 mm. wide ; relation of body 

 length to wing, 1:1; Sc pilose along basal fifth ; Ri pilose and spiny 

 along distal half, very few hairs among the spines ; R2+3 pilose except 

 for very minute basal section ; Cu2 arcuate ; discal cell absent. 



Legs: Leg i, length, 2.8 mm.; coxa and trochanter light brown; 

 femur light brown with apical dark ring ; tibia with its basal and 

 apical fourths black, the median part light brown ; tarsus black. Leg 2, 

 length, 2.5 mm. ; coxa and trochanter brown ; femur brown on basal 

 three-fourths, black on apical fourth ; tibia with its basal and apical 

 thirds black, the median third brown ; basal three-fourths of basitarsus, 

 basal two-thirds of second segment, and basal half of third segment 

 tan, the apical parts of these segments, as well as all of segments 4 

 and 5, black. Leg 3, length, 3.2 mm. ; coxa dark brown ; trochanter 

 brown; femur and tibia with basal three-fourths brown, the apical 

 fourths black ; basal two-thirds of basitarsus and basal half of second 

 segment tan, the remainder of these segments, as well as all of seg- 

 ments 3-5, black; relation of basitarsus to second segment, 5.4: i; 

 calcipala well developed, surpassing the pedisulcus ; pedisulcus well 

 formed one-third the distance from the base of second segment ; claw 

 with well-developed heel and with strong subbasal tooth (pi. 35, fig. 

 249). 



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

 long dark-brown hairs that reach only to segment 2. Segment 2 

 brown, pleura white-pruinose. Other segments shiny black, covered 

 with short black hairs. Sternites tan. 



Genitalia: Cercus (pi. 32, fig. 196) higher than long (wide), the 

 posterior angles well rounded, rather small. Anal lobe (pi. 32, fig. 



