NO. I BLACK FLIES OF GUATEMALA — DALMAT 239 



teeth, the central tooth and the outermost tooth on either side larger 

 than the others ; ventrolateral row composed of 6-10 hairs usually in 

 a straight row, the two basal ones at times out of line ; hairs bifid or 

 trifid ; lateral margin of submentum with 6 toothlike serrations, the 

 apical two appearing to arise from the lateral margin of the outermost 

 of the apical teeth. Occipital cleft dome-shaped (pi. 43, fig. 422). 



Thorax and Abdomen : Pseudopod (thoracic proleg) with 34-40 

 rows of hooks on its apex ; postclypeal sclerites small but well sclero- 

 tized. Posterior sucker with 86-97 rows of hooks. Anal gills with 3 

 main divisions, the middle one with 9 fingerlike projections and the 

 lateral ones each with 11-12 projections; some of the projections are 

 longer than others, each of the main divisions with at least one pro- 

 jection that is twice the size of any other. Posterior arms of X-shaped 

 sclerite very heavily pigmented and well sclerotized, reaching across 

 the entire dorsum of segment ; anterior arms not visible without clear- 

 ing, owing to the presence of a very heavily pigmented quadrangular 

 patch over each of these arms ; no rectal scales but with groups of 

 simple spines lateral to the region between the anterior and posterior 

 arms. Eighth segment without ventral papillae or sclerotized plaques. 



Types. — Pupa, in the collection of J. Romeo de Leon ; collected 

 from a stream in the high region called Maria Tecun, between Solola 

 and Totonicapan, Guatemala, 1940. 



SIMULIUM (HEARLEA) BURCHI Dalmat 



Simulium (Hearleu) hurchi Dalmat, Ann. Ent. Soc. Amer., vol. 44, No. i, pp. 

 42-47, figs. 16-23, 1951 (original description, d*, ?, and pupa). 



Male (pi. 26, figs. 94-96). — 3.0 mm. long. 



Head: Holoptic. Eyes reddish brown. Antenna 580 /a long, 11- 

 segmented, tapering; segment 3<i-|-2, 3>4-|-5, 3>ii; scape and 

 pedicel dark reddish brown, flagellum black. Palpi black. Clypeus 

 black, white-pruinose, with very long, strong black hairs. 



Thorax : Mesonotum velvety black, with band of white pruinosity 

 around the periphery, narrow along anterior margin, indented toward 

 center of mesonotum along midregion of anterior component ; long, 

 narrow, yellow, scalelike hairs sparsely distributed on mesonotum in 

 same regions as pruinosity, never in packets, these hairs being larger 

 in region of humeral angles; fine black hairs all over mesonotum, 

 longer in prescutellar region. Humeral angles black, with white prui- 

 nosity. Scutellum velvety black, with short, yellow, scalelike hairs and 

 long black hairs. Postnotum velvety black, with white pruinosity, 

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

 dark brown to black, the knob yellow, cup-shaped. Wings, 3.1 mm. 



