140 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



shaped apical teeth, the central tooth and the outermost tooth on either 

 side larger than the others ; ventrolateral row composed of 4 hairs, 

 arranged in a straight line ; hairs short, some bifid or trifid ; lateral 

 margin of submentum serrated, with about 6 toothlike indentations. 

 Occipital cleft dome-shaped, the apex somewhat pointed (pi. 42, 

 fig. 402). 



Thorax and Abdomen: Pseudopod (thoracic proleg) with 30-36 

 rows of hooks at its apex ; postclypeal sclerites minute, hardly visible. 

 Posterior sucker with 60-61 rows of hooks. Anal gills composed of 

 3 main branches, each with from 4-6 projections which extend as 

 fingers from a glove. Anterior and posterior arms of X-shaped scle- 

 rite well sclerotized, the anterior arms with a triangular-shaped ex- 

 tension on the outer margin and with a small rectangular membranous 

 patch between them near the point of divergence ; no rectal scales. 

 Two very small ventral papillae on segment 8; no plaques. 



Types. — Holotype {(^) and allotype (5), part mounted on slides, 

 the rest on pins, and numerous paratype ^(^, $$, and pupae in the 

 collection of the Instituto de Salubridad y Enfermedades Tropicales, 

 Mexico City ; collected on the Finca El Rosario, Soconusco, Chiapas, 

 Mexico, August 18, 1942. 



SIMULIUM (LANEA) DUGESI Vargas, Martinez, and Diaz 



Simulhim (Lanea) dugesi Vargas, Martinez, and Diaz, Rev. Inst. Salubr. 

 Enferm. Trop., vol. 7, No. 3, pp. 129-131, 167-168, figs. 45-48, 1946 (original 

 description, S, 9, pupa, and larva). 



Male (pi. 23, figs. 34-36). — 1.8 mm. long. 



Head : Holoptic. Eyes reddish brown on top, black on ventral half. 

 Antenna 11 -segmented, tapers markedly; scape and pedicel brown, 

 flagellum black. Palpi dark brown to black. Clypeus black, with white 

 pruinosity and with several short black hairs. 



Thorax : Mesonotum velvety dark reddish brown ; on each side of 

 midline is a large triangle of silver-gray pruinosity, the base contigu- 

 ous with the anterior margin of the scutum ; from the posterior apex 

 of the triangle extends a silver-pruinose band which joins with the 

 silver pruinosity of the prescutellar region ; in appearance, the silver- 

 pruinose designs look like funnels ; several long, narrow, golden, scale- 

 like hairs irregularly distributed on mesonotum, some almost copper- 

 colored, not in packets ; several tan hairs in prescutellar region, not 

 long. Humeral angles velvety dark brown, with white pruinosity. 

 Scutellum dark velvety brown, with some yellow scalelike hairs and 

 some long black ones. Postnotum dark velvety brown, with white 

 pruinosity, devoid of hairs. Pleura dark brown to black, with white 



