NO. I BLACK FLIES OF GUATEMALA — DALMAT 125 



short black hairs. Segments 6-9 shiny brown, with short black hairs 

 well distributed throughout. Sternites tan. 



Genitalia: Cercus (pi. 29, fig. 139) irregularly oval in shape, 

 somewhat more expanded ventrally, with a heavily sclerotized band 

 along its anterior margin. Genital rod (pi. 29, fig. 141) narrow, poorly 

 sclerotized, with no basal dilatation ; apical expansions of arms of 

 genital fork wide, subquadrangular in shape, with heavily sclerotized 

 bar extending diagonally across it ; with well-formed submedian tooth 

 on outer margin. Ovipositor (pi. 29, fig, 140) triangular in shape, its 

 base greater than its length. 



Pupa (pi. 36, fig. 283, and pi. 39, fig. 323). — Granulosity on entire 

 thorax; 4 simple and 2 bifid trichomes on either side of midline of 

 thorax. Dorsal surface of abdominal segments : Without granulosity ; 

 all spines on segments 2-4 are anteriorly directed, those on segments 7 

 and 8 are posteriorly directed ; segment 2 with 8 simple spines in 

 transverse row across its middle, the row divided in two by a median 

 space ; anterior to the outermost spines on either end of the row are 

 2 other similar spines ; segments 3 and 4 each with 8 simple spines in 

 transverse row somewhat before the posterior margin, with median 

 separation ; segment 7 with 12 simple spines in anterior row along 

 the anterior margin, with median space ; segment 8 with 22 simple 

 spines in transverse row slightly behind the anterior margin, with 

 median separation. Ventral surface of abdominal segments : Without 

 granulosity ; all spines are anteriorly directed, and all transverse rows 

 are situated three-fourths the distance from the anterior margin of 

 the respective segment ; segment 5 with 4 trifid spines in transverse 

 row, with median separation ; segments 6 and 7 each with 4 trifid 

 spines in transverse row, with median separation, the distance between 

 the two spines on either side of the midline greater than on segment 5. 

 Terminal spines absent. 



Respiratory apparatus (pi. 36, fig. 283) of each side arising slightly 

 behind the anterior margin of thorax ; composed of very short basal 

 trunk from which branch 8 thin filaments, grouped as follows : 3-3-2 ; 

 the filaments of each of the groups of three branch off close to one 

 another ; filaments with superficial segmentation and with microscopic 

 spicules. Maximum length, 2.5 mm., about equal to the length of 

 cocoon ; average diameter, 20 /x. 



Cocoon (pi. 39, fig. 323) : Length of base, 2.6 mm.; maximum 

 width, I.I mm.; maximum height, i.o mm. Cocoon of wall-pocket 

 type, without collar ; rim around anterior aperture thickened ; case with 

 parchmentlike texture, the threads visible. Cocoon covering abdomen 

 and half of thorax; attached along slightly more than the posterior 

 half of the base. 



