NO. I BLACK FLIES OF GUATEMALA — DALMAT 95 



Thorax : Mesonotum black, completely gray-pruinose ; long, nar- 

 row, appressed, yellow, scalelike hairs completely clothing the meso- 

 notum ; few long, fine, black hairs in prescutellar region. Humeral 

 angles black, the anterior margin brown, with yellow scalelike hairs. 

 Scutellum light brown, with yellow scalelike hairs and long black hairs. 

 Postnotum velvety dark brown, white-pruinose, devoid of hairs. 

 Pleura dark brown, with gray pruinosity ; pre-alar cluster composed 

 of golden-yellow hairs intermixed with a few black ones. Stem and 

 knob of halter light brown. Wings, 4.1 mm. long and 1.7 mm. wide; 

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

 fourths, at times with additional apical hair ; Ri completely pilose, the 

 apical fourth also with spines ; hairs arranged in several rows ; R2+3 

 completely pilose ; Cu2 arcuate ; discal cell present. 



Legs: Leg i, length, 3.8 mm.; completely brown. Leg 2, length, 



3.7 mm. ; coxa dark brown ; remainder of leg brown. Leg 3, length, 



4.8 mm. ; coxa dark brown ; trochanter brown ; femur, tibia, and tarsus 

 dark brown ; relation of basitarsus to second segment, 5.1 : i ; calcipala 

 well developed ; pedisulcus absent ; claw with basal heel developed into 

 long spur, and with lance-shaped process emerging at the base of 

 spur; inner face of claw with transverse striations (pi. 35, fig. 271). 



Abdomen : Tergite of segment i having the anterior half lighter 

 brown than the posterior half, clothed with short tan hairs ; pleurites 

 brown, with long tan hairs that reach segment 4. Segment 2 black, 

 with gray pruinosity and short black hairs. Other segments black, the 

 posterior margins brown, with short black hairs. Sternites tan, with 

 short black hairs. 



Genitalia: Cercus (pi. 28, fig. 121) somewhat rectangular in 

 shape, the posterior angles rounded ; height equal to twice the length 

 (width). Anal lobe (pi. 28, fig. 121) with dorsal extremity pointed, 

 expanded ventrally, similar to that of aguirrei. Genital rod (pi. 28, 

 fig. 123) without basal dilatation, or with it very poorly formed; 

 apical expansions of arms of genital fork ribbonlike, somewhat rec- 

 tangular in shape, with a slightly pigmented process at outer basal 

 angle. Ovipositors (pi, 28, fig. 122) triangular in shape, the base 

 greater than the length, the inner margins parallel to one another and 

 somewhat more heavily sclerotized. 



Pupa (pi. 36, fig. 277, and pi. 39, fig. 317). — (First description of 

 pupa other than of its respiratory apparatus.) Granulosity on entire 

 thorax ; 5 long, simple trichomes on either side of midline of thorax. 

 Dorsal surface of abdominal segments : Granulosity over entire sur- 

 face of all segments ; spines on segments 5-8 are posteriorly directed ; 

 segments 3 and 4 each with 8 simple anteriorly directed spines in a 



