NO. I BLACK FLIES OF GUATEMALA — DALMAT 1 63 



outer two simple or bifid, the inner two bifid ; the two spines on either 

 side of the midline of segments 6 and 7 are more separated than those 

 on segment 5, the distance between them approximately equal to that 

 of the median space. Terminal spines extremely small, the apices 

 rounded. 



Respiratory apparatus (pi. 36, fig. 291) of each side arising just 

 behind the anterior margin of the thorax, in the region of the humeral 

 angles ; composed of 8 filaments which branch as follows : 3-3-2 ; all 

 filaments have superficial annulations and microscopic spicules ; upon 

 gross examination the filaments appear very long and slender, all of 

 them close together. Maximum length of filaments, 3.9 mm., about 

 1 .2 times the length of the cocoon ; average diameter, 24 fi. 



Cocoon (pi. 39, fig. 331) : Length of base, 3.3 mm.; maximum 

 width, 1.5 mm.; maximum height, 1.4 mm. Cocoon of wall-pocket 

 type, without collar ; texture of case parchmentlike, the loose threads 

 appearing to be held in a somewhat gelatinous-appearing matrix ; rim 

 around anterior aperture thickened. Cocoon covering abdomen and 

 half of thorax ; attached along posterior half of base. 



Larva (pi. 40, fig. 370, and pi. 42, fig. 407). — Total length, 5.5-6.2 

 mm. Length of head capsule i.i times its width. Width of thorax 1.4 

 times width of head. Abdominal segments 1-4 equal to width of head ; 

 segments 5-7 expanded, greatest at segment 6 which is 1.9 times width 

 of segments 1-4 ; cross section and profile the same as for other species 

 of the subgenus Lanea. General color yellowish gray ; ventrolateral 

 patches not visible on segments 6 and 7. 



Head: Designs on frons-clypeus and epicranial plates shown on 

 plate 40, figure 370. Each cephalic fan with 39-42 pectinate branches, 

 the hairs on these branches all simple, heavy, short, rather close to- 

 gether except at the apices, not intermixed by longer or heavier hairs. 

 Mandible with 2 separate teeth on its inner margin, the basal one 

 about half the length of the more apical one, narrower and sharper. 

 Antenna 300 /x long, 4-segmented, all segments very dark brown, 

 just surpassing the basal stalk of the cephalic fan ; segment i shorter 

 than segments 2 or 3, segment 2 somewhat longer than 3 ; no trans- 

 verse striations. Submentum with 9 apical teeth, shaped like half of a 

 hexagon, all of approximately the same length ; ventrolateral row 

 composed of 3-5 hairs in a straight line, the most-apical two hairs 

 more separated from each other than any of the others, bifid and trifid ; 

 lateral margin of submentum with 7 toothlike structures ; two of these 

 are well sclerotized, arising just posterior to the outermost of the 

 apical teeth ; 4 others, also near the apex, are more like serrations ; 

 the most basal toothlike process, also appearing like a serration of 



