NO. I BLACK FLIES OF GUATEMALA — DALMAT 2O9 



figs. 83-86 and 150, 1946 (?, <S genitalia [photograph] pupa, and larva). — 

 Vargas and Diaz, Rev. Inst. Salubr. Enferm. Trop., vol. 9, No. 4, pp. 333- 

 334, 1948 (synonymized the Guatemalan species, SimuUum guatemalensis 

 De Leon, with this species). — Dalmat, Ann. Ent. Soc. Amer., vol. 44, No. i, 

 PP- 54-57, 1951 (distribution in Guatemala). 



Male (pi. 25, figs. 73-75). — (First complete description of male.) 

 2.5 mm. long. 



Head: Holoptic. Eyes rusty brown. Antenna 530 /a long, 11- 

 segmented, tapering; segment 3 long and narrow, 3=1+2, 3>4 + 5, 

 3>ii; scape and pedicel brown, the flagellum black. Palpi black. 

 Clypeus black, white-pruinose, i row of black hairs around periphery. 



Thorax : Mesonotum velvety black, with continuous band of white 

 pruinosity along the posterior and lateral margins ; near the humeral 

 angles on each side, the band bends posteriorly at a 45-degree angle, 

 continuing toward the center of the scutum rather than following the 

 anterior margin ; the ends of the band on each side terminate about 

 halfway between the lateral margin and the midline ; long, narrow, 

 yellow, scalelike hairs distributed over mesonotum, numerous on an- 

 terior third of scutum, in prescutellar region, and in narrow bands 

 along the lateral margins, few in central region ; those on prescutellar 

 area are somewhat longer; short black hairs distributed over entire 

 mesonotum, long black ones in prescutellar region. Humeral angles 

 brownish black, with white pruinosity. Scutellum black, with many 

 short, yellow, scalelike hairs and a few long black ones. Postnotum 

 velvety brown to black, white-pruinose, devoid of hairs. Pleura dark 

 brown, with white pruinosity. Stem of halter brown to black, the 

 knob yellow to orange. Wings, 2.7 mm. long and 1.2 mm. wide; 

 relation of body length to wing, 1:1.1; Sc pilose along basal sixth; 

 Ri pilose and spiny along distal half ; R0+3 pilose along distal four- 

 fifths ; Cuo arcuate ; discal cell absent. 



Legs: Leg i, length, 2.7 mm.; coxa and trochanter black; femur 

 and tibia black with numerous yellow scalelike hairs ; tarsus black. 

 Leg 2, length, 2.3 mm. ; leg colors and investiture like on leg i with 

 the exception of the basitarsus, which has a very small light-brown 

 basal ring. Leg 3, length, 2.9 mm. ; leg colors and investiture like on 

 legs I and 2 with the exception of the basitarsus, which has its basal 

 half brown ; relation of basitarsus to second segment, 4.8 : i ; calcipala 

 well developed, reaching the pedisulcus ; pedisulcus well formed one- 

 third the distance from the base of segment 2. 



Abdomen : Tergite and pleurites of segment i black, the pleurites 

 with long brown hairs that reach segment 5. Segment 2 black, with 

 white pruinosity. Other segments black, the pleurites of segments 5-7 



