NO. I BLACK FLIES OF GUATEMALA — DALMAT I9S 



Inst. Salubr. Enferm. Trop., vol. 3, No. 3, pp. 242-243, figs. 7 and 14, 1942 

 (c?and?). 



Sitnulium virgatum Coquillett, Vargas, Rev. Inst. Salubr. Enferm. Trop., vol. 4, 

 No. 4, figs. 33-35, 1943 (pupa). 



Simnlium (Dyarella) rubicunduhim Knab, Vargas, Martinez, and Diaz, Rev. 

 Inst. Salubr. Enferm. Trop., vol. 7, No. 3, pp. 179-180, fig. 160, 1946 

 (larva). — Dalmat, Ann. Ent. Soc. Amer., vol. 44, No. i, p. 35, 1951 (com- 

 pared with Sinmlimn (Dyarella) acatenangoensis, new species, and its 

 validity established). 



Male (pi. 24, figs. 64-66). — 3.5 mm. long. 



Head: Holoptic. E3^es light reddish brown. Antenna 640 ju,, 11- 

 segmented; segment 3>i-f2, 3<4 + 5, 3>ii; segment 4 much nar- 

 rovi^er than segment 3 ; scape and pedicel light brown, the flagellum 

 gradually becoming darker from base to apex. Palpi dark brown at 

 base, black at apex. Clypeus brown, white-pruinose, irregularly cov- 

 ered with black hairs. 



Thorax : Mesonotum yellowish brown, with rather wide band of 

 white pruinosity around periphery, widest at posterior margin ; 2 

 narrow longitudinal stripes of white pruinosity running from anterior 

 to posterior margin on either side of midline, connected with white 

 pruinosity of prescutellar region to form a lyre-shaped design ; a nar- 

 row dark-brown stripe along midline ; narrow, yellow, scalelike hairs 

 completely covering the mesonotum, never in packets, longer on pre- 

 scutellar area; short black hairs over entire surface of mesonotum, 

 long black ones on prescutellar region. Humeral angles shiny brown, 

 evenly white-pruinose. Pleura white-pruinose. Scutellum shiny 

 brown, with numerous long tan hairs and a few long black ones on 

 either side. Postnotum shiny brown, completely white-pruinose. Stem 

 of halter brown and hairy, the knob yellow. Wings, 3.6 mm. long and 

 1.5 mm. wide ; relation of length of body to wing, i : i ; Sc pilose along 

 its basal fourth ; Ri pilose and spiny along the distal half ; R2+3 pilose 

 along its distal four-fifths ; Cu2 arcuate ; discal cell absent. 



Legs: Leg i, length, 4.1 mm.; coxa and trochanter tan; femur 

 light brown except for apical fourth which is dark brown ; basal two- 

 thirds of tibia tan, remainder black ; tarsus black. Leg 2, length, 3.6 

 mm. ; coxa brown ; trochanter light brown ; femur tan on basal three- 

 fourths, remainder dark brown ; basal three-fourths of tibia tan with 

 dark-brown spot near middle of anterior edge, remainder dark brown ; 

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

 light brown, the remainder of these segments, as well as all of seg- 

 ments 3-5, black. Leg 3, length, 4.2 mm. ; coxa dark brown ; tro- 

 chanter tan ; basal two-thirds of femur tan, apical third dark brown ; 

 basal third of tibia tan with a dark-brown ring, remainder black ; basal 



