NO. I BLACK FLIES OF GUATEMALA — DALMAT 263 



of hooks. Anal gills with 3 main divisions, broad and fleshy, the two 

 outer divisions each with 12 slender, blunt, fingerlike branches and 

 the median division with 13 branches ; all branches seem to emerge at 

 the same level and are about equal in length. Anterior arms of X- 

 shaped sclerite somewhat obscured by dark patches along the posterior 

 margins; posterior arms well sclerotized; 3 to 4 irregular rows of 

 groups of rectal spines, each group composed of 3-4 spines ; 30 to 40 

 spines on each side between the anterior and posterior arms. No 

 ventral papillae or plaques on eighth segment. 



Types. — Holotype ($), pinned, collected from the Rio Los Arcos, 

 near Los Encuentros, Department of Solola, Guatemala, November 4, 

 1948; allotype (J*, dissected from pupal skin), on 3 slides, collected 

 from same stream as holotype, December 13, 1948; paratypes, 4 $$, 

 I c^> 27 pupae ; ideotypes, 2 J* J*. The holotype and allotype are in the 

 collection of the United States National Museum ; the paratypes and 

 ideotypes are in the collection of Herbert T. Dalmat. 



SIMULIUM (HEARLEA) LARVISPINOSUM De Leon 



Simulium (Hearlea) larvispinosum De Leon, Impreso No. 56, Inst. Invest. 

 Cient., Univ. San Carlos, Guatemala, pp. 5-23, figs. 1-19, 1948 (original de- 

 scription, c?, ?, pupa, and larva). 



Simulium {Hearlea) carolinae De Leon, Vargas and Diaz, Rev. Inst. Salubr, 

 Enferm. Trop., vol. 9, No. 4, p. 2,^7, 1948 (considers larvispinosum synonym 

 of carolinae). 



Male (pi. 27, figs. 109-111). — 3.2 mm. long. 



Head: Holoptic. Eyes dark reddish brown. Antenna 550 ju. long, 

 1 1 -segmented, tapering; segment 3<i+2, 3>4+5, 3>ii; segment 2 

 widest ; segment 3 long and slender ; scape and pedicel brown, flagel- 

 lum black. Palpi black. Clypeus black, white-pruinose, irregularly 

 covered with long black hairs. 



Thorax : Mesonotum velvety black, with narrow band of white 

 pruinosity around the periphery, the band interrupted only in the 

 middle of the anterior margin where it is somewhat diffuse ; that part 

 of band which is contiguous with the anterior margin is rather nar- 

 row ; long, narrow, copper-yellow, scalelike hairs in narrow, irregular 

 band around periphery, never in packets ; some long black hairs in 

 prescutellar region. Humeral angles black, with white pruinosity. 

 Scutellum shiny black, with several long, yellow, scalelike hairs and 

 with some long black hairs. Postnotum velvety black, white-pruinose, 

 devoid of hairs. Pleura black, with white pruinosity. Stem of halter 

 black, the knob yellow. Wings, 3.4 mm. long and 1.4 mm. wide; rela- 

 tion of length of body to wing, 1:1.1; Sc pilose along basal sixth; 



