92 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



each side of segment 9, there emerge from the margin 2 bifid and 3 

 simple long hairs. Each abdominal segment encircled by a dark band 

 along its anterior two-thirds to three-fourths. Terminal spines very 

 well developed, sclerotized, about 60 fi long. 



Respiratory apparatus (pi. 36, fig. 276) of each side arising slightly 

 behind the anterior margin of the thorax, in the region of the humeral 

 angles ; composed of 2 long, tubular filaments, tapered at apex, both 

 arising at base of apparatus, so arched as to form a V. Both elements 

 with superficial transverse annulations along their entire length and 

 with minute spicules, never subdivided. Maximum length, 2.5 mm., 

 about 1.3 times the length of cocoon ; average diameter, 0.2 mm. 



Cocoon (pi. 39, fig. 316): Length of base, 2.0 mm.; maximum 

 width, 1.3 mm.; maximum height, 1.3 mm. Cocoon of wall-pocket 

 type, without collar; rim around anterior aperture not thickened, 

 rarely with dorsal prolongation ; case composed of very loose threads 

 that are intermixed with particles of earth and other material. Cocoon 

 covering one-half of abdomen only ; attached approximately along the 

 posterior 0.8 of its base. 



Larva (pi. 40, fig. 356, and pi. 42, fig. 393). — (First description of 

 larva.) ^ Total length, 6.3 mm. Length of head capsule 1.2 times its 

 width. Width of thorax 1.3 times that of head. First four abdominal 

 segments i.i times width of head; segments 5-7 expanded, greatest 

 at segment 6 which is 1.5 times segments 1-4; cross section of body 

 oval; thorax and abdominal segments 1-4 less expanded than in mem- 

 bers of the subgenus Simulium. General color gray, with very long, 

 dark patches on ventrolateral regions of segments 6 and 7. 



Head: Designs on frons-clypeus and epicranial plates shown on 

 plate 40, figure 356. Each cephalic fan with 30-35 pectinate branches, 

 the hairs on these branches simple, rather long and close together, 

 with somewhat heavier simple hairs at regular intervals. Mandible 

 with 23 sharp-pointed teeth on its inner margin, contiguous to one 

 another, only the most-distal somewhat longer than the others. An- 

 tenna 430 ju, long, 4-segmented, pale yellow ; just about reaching the 

 end of basal stalk of cephalic fan; segment 3 is 1.7 times the length 

 of segment 2 which is 1.2 times the length of segment i ; no transverse 

 striations. Submentum with 13 apical teeth arranged in three project- 

 ing groups, the middle group composed of a central long tooth and a 

 shorter one to each side near its base, each lateral group composed 

 of a central long tooth, a somewhat shorter tooth to each side reaching 

 its midregion, and another still shorter tooth to each side near the 



^ Since the date this work was submitted for publication, a description of the 

 larva was published by L. Vargas and A. Diaz N. (1952). 



