NO. I BLACK FLIES OF GUATEMALA — DALMAT 207 



only otnall, bulblike dilatation ; apical expansions of arms of genital 

 fork triangular in shape, the apical angle very sharply pointed and 

 heavily sclerotized ; the outer basal angles somewhat rounded and 

 pigmented ; the inner angle with a very long conical projection ex- 

 tending from it. Ovipositor (pi. 32, fig. 191) long, lance-shaped. 



Pupa (pi, 37, fig. 300, and pi. 39, fig. 340). — Thorax with granu- 

 losity only on its posterior fourth ; i bifid, 3 trifid, and 2 arborescent 

 trichomes on either side of midline of thorax. Dorsal surface of ab- 

 dominal segments : Segments i and 2 with granulosity on their 

 posterior margins ; segment 2 with 6 anteriorly directed simple spines 

 in transverse row somewhat anterior to posterior margin, the row 

 being divided into two by a median space; segments 3 and 4 with 

 transverse rows of 8 spines, situated as on segment 2, each row also 

 being separated into two by a median space. Ventral surface of ab- 

 dominal segments : Without granulosity ; segment 5 with 4 anteriorly 

 directed simple spines in transverse row a little before posterior mar- 

 gin, the spines being divided into two equal groups by a median space ; 

 segments 6 and 7 with similar rows of spines, but with the two spines 

 on either side of the median space more separated than on segment 5, 

 the distance between them being approximately equal to that of the 

 median space. Terminal spines absent. 



Respiratory apparatus (pi. 37, fig. 300) of each side arising behind 

 anterior margin of thorax, each composed of 8 filaments which branch 

 as follows : 2-1 -2-2-1 ; filaments with superficial annulations and 

 covered with microscopic spicules. Maximum length of filaments, 

 1.3 mm., about 0.25 times the length of the cocoon ; average diameter, 

 44 /i. 



Cocoon (pi. 39, fig. 340) : Length of base, 4.0 mm. ; maximum 

 length, 5.2 mm. ; maximum width, 2.1 mm. ; maximum height, 1.8 mm. 

 Cocoon slipper-shaped, with distinct collar and fine parchmentlike 

 texture, threads not visible ; no festoons or prolongations from margin 

 of anterior aperture ; in profile, the margin of the anterior aperture is 

 sinuous, with a very slightly hardened rim. Cocoon covering abdomen 

 and half of thorax. 



Larva (pi. 41, fig. 378, and pi. 42, fig. 415). — (First description 

 of larva.) Total length, 6.8-7.9 mm. Length of head capsule i.i times 

 its width. Width of thorax 1.5 times width of head. Abdominal seg- 

 ments 1-4 about equal in width to thorax; segments 5-7 about 1.2 

 times width of segments 1-4; general expansion of abdomen from an- 

 terior to posterior ends, the posterior end narrowing rapidly ; in pro- 

 file, the larva appears the same as others of the subgenus Dyarella. 



