NO. I BLACK FLIES OF GUATEMALA — ^DALMAT I93 



ments with almost bluish cast ; pleura of all of these segments brown- 

 ish, with white pruinosity. Sternites brown, with yellowish pruinosity. 



Genitalia: Cercus (pi. 31, fig. 181) oval in shape, slightly higher 

 than long (wide), clothed with posteriorly directed, long, strong hairs, 

 and with many minute spinelike hairs. Height of anal lobe (pi. 31, 

 fig. 181) twice its length (width), with broad projection just beneath 

 the cercus. Genital rod (pi. 31, fig. 183) with bulblike basal dilata- 

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

 apical and outer basal angles well sclerotized and sharply pointed, the 

 inner basal angle membranous and blunt ; outer margin of triangle also 

 well sclerotized. Ovipositor (pi. 31, fig. 182) long, lance-shaped, 

 well tapered to apical point. 



Pupa (pi. 37, fig. 297, and pi. 39, fig. 337). — Entire thorax with 

 granulosity ; trichomes absent on dorsum of thorax. Dorsal surface 

 of abdominal segments: Granulosity present on segments 1-4; seg- 

 ment 2 with 6 anteriorly directed spines in transverse row three- 

 fourths of the way back from anterior margin, the row being divided 

 in two by a median space ; lateral to the terminal spine at each end of 

 the row are 3 somewhat smaller spines arranged in a triangular pat- 

 tern; segments 3 and 4 with transverse rows composed of 8 spines, 

 situated a little before the posterior margin, each row also being sepa- 

 rated into two by a median space. Ventral surface of abdominal seg- 

 ments : Fifth segment with 4 anteriorly directed spines in transverse 

 row, situated near the posterior margin, the spines being divided into 

 two equal groups by a median space ; at times this row of spines is lack- 

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

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

 so that the distance between them is approximately equal to that of 

 the median space. Terminal spines absent. 



Respiratory apparatus (pi. 37, fig. 297) of each side arising some- 

 what behind the anterior margin of thorax; composed of 10 filaments 

 which branch in groups as follows: 4-4-1-1. Maximum length of 

 filaments, 0.9 mm., about 0.2 times the length of cocoon ; average di- 

 ameter, 36 /u,; filaments with superficial annulation and with micro- 

 scopic spicules. 



Cocoon (pi. 39, fig. 337) : Length of base, 3.2 mm. ; maximum 

 length, 4.2 mm. ; maximum width, 1.9 mm. ; maximum height, 2.0 mm. 

 Cocoon slipper-shaped, with distinct collar and fine parchmentlike 

 texture, threads not visible ; without festoons or prolongations ; rim 

 around anterior aperture not thickened. Cocoon covering abdomen 

 and half of thorax. 



Larva (pi. 40, fig. 375, and pi. 42, fig. 412). — Total length, 5.2 mm. 



