NO. I BLACK FLIES OF GUATEMALA — DALMAT 267 



mensions (not short and broad as in caroUnae), with 2 teeth (or i 

 bifid tooth) on its inner margin, these apparently emerging from the 

 same base, the more-distal one somewhat broader. Antenna 390 /a 

 long, 5-segmented, yellow, segments 1-3 alone reaching the end of the 

 basal stalk of cephalic fan ; segment i>2>3<4 = 2; segment 2 super- 

 ficially divided into two segments not far from its base, with white 

 patch at the division; segment i with white patch near its base and 

 with longitudinal striations ; white patch at union of segments 2 and 3. 

 Submentum with 9 apical teeth, triangular in shape, the central tooth 

 and the outermost on either side larger than the others ; ventrolateral 

 row composed of 13 hairs plus a small one near the base of submen- 

 tum ; hairs arranged in irregular line, the basal six hairs appear simple, 

 the next four to five hairs trifid, and the apical two bifid ; lateral mar- 

 gin of submentum with 3 toothlike indentations. Occipital cleft with 

 its sides almost parallel, the apex strongly concave (pi. 43, fig. 428). 



Thorax and Abdomen: Pseudopod (thoracic proleg) with 72-74 

 rows of hooks at its apex ; postclypeal sclerites long, narrow, poorly 

 sclerotized, appearing to be extensions from the posterior junction of 

 the frons-clypeus and epicranial plates. Posterior sucker with 191-195 

 rows of hooks. Anal gills with 3 main divisions that are short and 

 fleshy, each with from 8 to 10 fingerlike projections that are of differ- 

 ent length but more or less of the same diameter, giving a total of 25- 

 28 branches. Anterior arms of X-shaped sclerite well sclerotized, 

 rather short and broad ; posterior arms completely encircling the pos- 

 terior sucker, well sclerotized, slender; lateral to the union with the 

 anterior arms, the posterior arm of each side bears 2 heavily sclerotized 

 and pigmented triangular plates that are erect, with the apex pointing 

 dorsally ; also arising lateral to the dorsal ones there is a ventrally di- 

 rected plate which is strongly serrated as though to form a comb of 

 broad, heavy teeth ; simple, minute scales between anterior and poste- 

 rior arms of either side ; rectal scales absent ; 2 very broad dark-brown 

 bands, one on either side of the midline, transversely crossing the larva 

 just in front of the anal gills ; these extend from near the midline to 

 the base of the ventrally directed plate and can be used to distinguish 

 this species from caroUnae and from all other Guatemalan species. No 

 ventral papillae or plaques on eighth segment. 



Types. — Larva, pupa, $, and J*, the $ and (^ apparently dissected 

 from pupal skins ; in collection of J. Romeo de Leon ; collected in a 

 small waterfall on the Finca Olas de Moca, Chicacao, Department of 

 Suchitepequez, Guatemala. 



Although Vargas and Diaz (1948) synonymized this species with 

 caroUnae, there seems to be little doubt that the two species are dis- 



