NO. I BLACK FLIES OF GUATEMALA — DALMAT 143 



expansions of arms of genital fork triangular in shape, the apical 

 angle strongly tapered and pointed ; a long toothlike extension near 

 the base from the outer margin ; all hyaline. Ovipositor (pi. 29, fig. 

 152) very small, much longer than wide, its apex pointed. 



Pupa (pi. 36, fig. 287, and pi. 39, fig. 327). — Granulosity dense on 

 entire thorax ; 4 bifid trichomes on either side of midline. Dorsal 

 surface of abdominal segments : No granulosity ; spines on segments 

 2-4 are anteriorly directed, those on segments 7-9 are posteriorly 

 directed; segment 2 with 8 simple, hairlike spines in transverse row 

 across the middle, the row divided into two by a median space; an- 

 terior to the outermost spine on either side of the row are 2 hairs ; 

 segments 3 and 4 with 8 simple spines in a transverse row somewhat 

 before the posterior margin, the row divided by a median space ; seg- 

 ment 7 with 10 simple spines in transverse row behind the anterior 

 margin, with median separation, and with comblike groups of spines 

 lateral to both ends of the row ; segment 8 with 24 simple spines in 

 transverse row behind the anterior margin, with median separation, 

 and with combs lateral to both ends of the row; segment 9 with 24 

 spines in irregular transverse row behind the anterior margin, not 

 interrupted by median space, with combs lateral to both ends of the 

 row ; on either side of midline, near the posterior end of the ninth seg- 

 ment, is a single short, heavy spine. Ventral surface of abdominal 

 segments : No granulosity ; all spines are anteriorly directed ; seg- 

 ment 4 with I bifid spine on either side of midline, about three-fourths 

 the distance from the anterior margin ; segment 5 with transverse row 

 of 4 bifid spines, about three-fourths the distance from the anterior 

 margin, divided by median space ; segments 6 and 7 with 4 spines in 

 a transverse row about three- fourths the distance from the anterior 

 margin, the outer spines simple, the inner spines bifid ; the two spines 

 on either side of the midline are more separated than those on seg- 

 ment 5, the distance between them approximately equal to that of the 

 median space. Terminal spines very small, pointed. 



Respiratory apparatus (pi. 36, fig. 287) of each side arising just 

 behind the anterior margin of thorax ; composed of 8 filaments which 

 branch as follows : 3-3-2 ; with poorly marked superficial annulations 

 and with microscopic spicules. Maximum length of filaments, 1.9 mm., 

 about 0.65 times the length of the cocoon ; average diameter, 16 /a. 



Cocoon (pi. 39, fig. 327) : Length of base, 2.9 mm.; maximum 

 width, 1 .8 mm. ; maximum height, i .4 mm. Cocoon of wall-pocket 

 type, without collar ; texture of case parchmentlike, the threads visi- 

 ble ; rim around anterior aperture thickened. Cocoon covering abdo- 

 men and half of thorax ; attached along posterior half of its base. 



