NO. I BLACK FLIES OF GUATEMALA — DALMAT 219 



from apex to median expansions. Ovipositor (pi. 32, fig. 200) short 

 and broad, triangular in shape. 



Pupa (pi. 37, fig. 303, and pi. 39, fig. 343) • 



Respiratory apparatus (pi. 37, fig. 303) of each side arising slightly 

 behind anterior margin of thorax; composed of 3 inflated, tubelike 

 bran:hes, arranged one above the other, the longest one dorsal; with 

 annulations. The branches, from the dorsal to the ventral one, meas- 

 ure 2.1 mm., 1.8 mm., and 1.3 mm. 



Cocoon (pi. 39, fig. 343) : Wall-pocket type, without collar; roof 

 subparallel to substratum; ventral surface with its midregion fixed 

 to substratum, its anterior fourth slightly raised and its posterior third 

 markedly raised to meet the roof ; ventral surface woven along ap- 

 proximately the posterior three-fourths of its extent ; anterior aperture 

 very slightly thickened. 



Larva (pi. 41, fig. 381, and pi. 43, fig. 418). — (First description 

 of larva.) Total length, 6.2 mm. Length of head capsule i.i times its 

 width. Width of thorax 1.5 times that of head. Abdominal segments 

 1-4 equal to 1.2 times width of head ; segments 5-7 expanded, greatest 

 at segment 6 which is 1.6 times width of segments 1-4. General color 

 gray, with dark patches on ventrolateral areas of segments 6 and 7. 



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

 plate 41, figure 381. Each cephalic fan with 28 pectinate branches, the 

 hairs on these branches small, simple, well separated, interspersed at 

 regular intervals with stronger bifid hairs. Mandible with 2 teeth 

 along its inner margin, one well-formed, pointed tooth and one ex- 

 tremely small tooth that appears to emerge from near the base of the 

 other. Antenna 390 {x long, 4-segmented, dark brown, about as long 

 as basal stalk of cephalic fan ; segments 2 and 3 subequal, 2 somewhat 

 longer than i ; segments i and 2 with transverse striations. Submen- 

 tum with 9 apical teeth, each like half a hexagon in shape, the central 

 tooth and the outermost tooth on either side longer than the others ; 

 ventrolateral row composed of 7 hairs in a straight line, the basal 

 lateral margin of submentum with 6 toothlike processes, the four more- 

 basal ones appearing more like serrations of the margin, the two apical 

 ones like heavily sclerotized teeth ; the latter appear to arise from the 

 side of the outermost of the apical teeth. Occipital cleft small, with 

 liplike projection from its rounded apex (pi. 43, fig. 418). 



Thorax and Abdomen : Pseudopod (thoracic proleg) with 38-40 

 rows of hooks at its apex ; postclypeal sclerites very small, thin, well 

 separated. Posterior sucker with 78-82 rows of hooks. Anterior and 

 posterior arms of X-shaped sclerite well sclerotized, the anterior arms 

 completely covered by a large patch which extends from the region 



