268 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



tinct. They can be separated easily in the larval and pupal stages and 

 by the male and female genitalia. The differences have, in part, been 

 brought out in the keys. 



SIMULIUM (HEARLEA) MICROBRANCHIUM Dalmat 



Siwulium (SitnuHum) microbranchium Dalmat, Ann. Ent. Soc. Amer., vol. 42, 

 No. 4, pp. 538-544, figs. 1-9, 1949 (original description, ?, <S genitalia, and 

 pupa). 



Simulium (Hearlea) microhranchitim Dalmat, Ann. Ent. Soc. Amer., vol. 44, 

 No. I, pp. 50-52, 1951 (male). 



Male (pi. 27, figs. 112-114). — 3.0 mm. long. 



Head: Holoptic. Eyes reddish brown. Antenna 680 ju. long, 11- 

 segmented, slightly tapering; segment 3<i-l-2, 3>4+5, 3>ii; 

 black. Palpi black. Clypeus black, w^hite-pruinose, irregularly covered 

 with long black hairs. 



Thorax : Mesonotum velvety black, with band of white pruinosity 

 around entire periphery, usually interrupted at middle of anterior mar- 

 gin ; at times the lateral arms are so broad that all but the center of 

 the scutum is covered; long, narrow, yellow scalelike hairs in wide 

 band around periphery of mesonotum, the band widest on anterior and 

 posterior margins ; these hairs are longer in prescutellar region ; long 

 black hairs on prescutellar region ; pre-alar group composed of a clus- 

 ter of long yellow hairs. Humeral angles black, with white pruinosity. 

 Scutellum black, with numerous short, yellow, scalelike hairs and with 

 few long black hairs. Postnotum dark velvety brown, with white prui- 

 nosity, devoid of hairs. Pleura dark brown, white-pruinose. Stem of 

 halter dark brown to black, the knob yellow. Wings, 3.4 mm. long 

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

 along basal sixth ; Ri pilose and spiny along distal half ; R2+3 pilose 

 except for very short basal section ; Cua arcuate ; discal cell absent. 



Legs: Leg i, length, 3.1 mm.; coxa and trochanter light brown; 

 femur light brown with very small black apical ring; outer surface 

 and anterior edge of tibia tan, the inner surface and posterior margin 

 black. Leg 2, length, 2.7 mm. ; coxa black ; trochanter dark brown, its 

 central region black ; femur brown, with very small apical black ring ; 

 basal half of tibia and of basitarsus light brown, their apical halves 

 black ; tarsal segments 2-5 black. Leg 3, length, 3.5 mm. ; coxa black ; 

 trochanter brown ; femur with basal half to three-fourths brown, the 

 apical portion black ; tibia tan on basal third to half, the apical part 

 black ; basal half of basitarsus tan, apical half black ; tarsal segments 

 2-5 black ; relation of basitarsus to second tarsal segment, 4.3 : i ; cal- 

 cipala well developed but not reaching pedisulcus ; pedisulcus well 

 developed on basal third of second segment. 



