NO. I BLACK FLIES OF GUATEMALA — DALMAT I53 



hairs and short black ones. Cornuae of buccopharyngeal apparatus 

 sclerotized, with winglike expansions ; median space somewhat sclero- 

 tized, with several rather long, well-developed, sharply pointed teeth 

 along entire extent. 



Thorax: Mesonotum orange; 2 narrow longitudinal stripes of 

 white pruinosity, one on either side of midline, extending from trans- 

 verse row of white pruinosity, situated along the anterior margin of 

 mesonotum, to prescutellar depression which is also white-pruinose ; 

 the longitudinal stripes are wider at the anterior margin and they curve 

 outward near their posterior limit; narrow band of white pruinosity 

 along lateral margins ; short, narrow, yellow, scalelike hairs along the 

 periphery, more in the prescutellar region ; short black hairs on dor- 

 sum, principally along anterior and posterior margins. Humeral angles 

 pale yellow, with white pruinosity. Scutellum yellow, darker near 

 midline, with white pruinosity. Postnotum brown on anterior half, 

 yellow on posterior half, with white pruinosity, devoid of hairs. Pleura 

 light brown, partially white-pruinose. Stem of halter brown, the knob 

 pale yellow. Wings, 2.1 mm. long and i.o mm. wide ; relation of body 

 length to wing, i : i ; Sc pilose along basal two-thirds ; Ri completely 

 pilose, with spines also along distal half ; R2+3 pilose except for a very 

 short basal section (long enough for only one hair) ; Cua arcuate; 

 discal cell absent. 



Legs : Leg i, length, 2.2 mm. ; coxa, trochanter, and femur yellow ; 

 tibia yellow with brown apical ring; tarsus black. Leg 2, length, 1.9 

 mm. ; coxa dark brown ; trochanter, femur, tibia, and basitarsus 

 yellow; tarsal segment 2 yellow on basal half, black on apical half; 

 tarsal segments 3-5 black. Leg 3, length, 2.4 mm. ; coxa dark brown 

 at base, light brown at apex ; trochanter yellow ; femur yellow with 

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

 basal two-thirds of basitarsus and basal half of second tarsal segment 

 yellow, the remainder of these segments, as well as all of segments 

 3-5, dark brown to black; relation of basitarsus to second segment, 

 4:1; calcipala well developed, long and slender, surpassing the pedi- 

 sulcus ; pedisulcus well formed at middle of second segment ; claw with 

 basal heel very slightly developed, without secondary spur or tooth 

 (pi. 35, fig. 264). 



Abdomen : Tergite of segment i yellow, with short yellow hairs ; 

 pleurites yellow, with long yellow hairs reaching segment 3. Segment 

 2 yellow with short black hairs. Segments 3-6 yellow with black 

 median patch and with one or two smaller dark patches on each side 

 of the median one ; this gives the appearance of longitudinal rows of 

 spots ; segments 7 and 8 yellow, with white pruinosity. Sternites tan, 

 with a few long black hairs on last segment. 



