204 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I25 



rows of hooks on its apex ; postclypeal sclerites small, well sclerotized, 

 very dark, one at each posterior junction of the frons-clypeus with an 

 epicranial plate. Posterior sucker with 450-460 rows of hooks. Anal 

 gills with 3 main branches, these being fleshy but not very large ; from 

 each base extend 19 fingerlike prolongations which are short but not 

 stubby. The X-shaped sclerite well sclerotized, its anterior arms with 

 winglike structures at the ends ; with 6 to 7 rows of rectal scales which 

 are either single, bifid, or trifid, the patch extending to lateral margins 

 of the larva. No ventral papillae or plaques on eighth segment. 



Types. — Holotype ($), allotype (J*), and paratypes (i (^ and 

 3 $?) in the collection of the Instituto de Salubridad y Enfermedades 

 Tropicales, Mexico City; collected from the stream El Rubi, Finca 

 El Vergel, Chiapas, Mexico, 1,000 meters above sea level, January 

 1945- 



SIMULIUM (DYARELLA) YEPOCAPENSE Dalmat 



Simulium (Dyardla) yepocapense Dalmat, Ann. Ent. Soc. Amer., vol. 42, 

 No. 4, pp. 548-553, figs. 23-28, 1949 (original description, S, 5, and pupa). 



Male (pi. 25, figs. 70-72). — 3.3 mm. long. 



Head: Holoptic. Eyes reddish brown. Antenna 570 ju,, ii-seg- 

 mented; segment 3>i-|-2, 3<4+5, 3<ii; appears widest at seg- 

 ments 8 and 9 ; scape and pedicel light brown, flagellum dark brown. 

 Palpi dark reddish brown. Clypeus grayish brown, white-pruinose, 

 with short tan hairs. 



Thorax : Mesonotum coppery brown, with 2 very wide longi- 

 tudinal bands of white pruinosity, one on either side of midline ; each 

 band is approximately one-fourth the width of the dorsum ; a very 

 narrow black line running down the midline ; periphery of mesonotum 

 white-pruinose except for break at center of anterior margin ; broad, 

 yellow, scalelike hairs over entire mesonotum, never in packets, 

 longer in prescutellar region ; short black hairs entirely covering the 

 mesonotum longer in prescutellar region. Humeral angles white- 

 pruinose, with very pale-yellow scalelike hairs. Scutellum grayish 

 brown, white-pruinose, with yellow scalelike hairs and longer black 

 ones. Postnotum velvety brown, with white pruinosity ; devoid of 

 all hairs. Pleura white-pruinose. Stem of halter brown, knob tan. 

 Wings, 3.4 mm. long and 1.4 mm. wide ; relation of length of body to 

 wing, I : I ; Sc pilose along its apical third ; Ri pilose and spiny along 

 distal three-fifths, beginning at point where R2+3 emerges ; R2+3 pilose 

 along distal two-thirds ; Cuo arcuate ; discal cell absent. 



Legs : Leg i, length, 3.6 mm. ; coxa brown ; trochanter light brown ; 



