NO. I BLACK FLIES OF GUATEMALA — DALMAT 123 



pying about half its width ; calcipala very well developed, surpassing 

 the pedisulcus ; pedisulcus well formed one-third the distance from 

 the base of second tarsal segment. 



Abdomen : Tergite and pleurites of segment i velvety brown, the 

 pleurites with fringe of long brown hairs that reach segment 3, and 

 the tergite with very short brown hairs. Segment 2 dark brown, com- 

 pletely white-pruinose, with short brown hairs. All remaining seg- 

 ments dark velvety brown, with short black hairs ; pleural regions of 

 segments 3, 5, 6, 7, and 8 white-pruinose ; segment 9 completely gray- 

 to tan-pruinose, with few short black hairs, finer than on other 

 segments. 



Genitalia: Sidepiece (pi. 22, fig. 23) somewhat cylindrical in 

 form, longer than wide, the apical margin very slightly shorter than 

 the basal one ; basal and apical margins parallel to each other ; dorsal 

 opening occupying about two-thirds of the dorsal surface of sidepiece. 

 Clasper (pi. 22, fig. 23) 0.6 the length of sidepiece, conical in shape, 

 the apex somewhat truncate, with a very short heavy terminal spine 

 at the more basal of the apical angles ; basal opening extending along 

 one-third of clasper. Body of adminiculum (pi. 22, fig. 24) triangular 

 in shape, wider than long, covered with numerous hairs, longer on 

 apical margin ; basal processes long and broad, as long as the body of 

 adminiculum, the ends somewhat spatulate, pointed, and convergent. 

 Adminicular arms (pi. 22, fig. 22) with about 6 long, sharp teeth, well 

 spaced, arranged in linear fashion ; lateral plate small, quadrangular, 

 with numerous wrinkles that appear somewhat sclerotized. 



Female (pi. 29, figs. 139-141, and pi. 35, fig. 275). — 2.0 mm. long. 



Head : Dichoptic. Eyes shiny black ; height of f ronto-ocular tri- 

 angle 1.5 times the base. Antenna 400 fi long, i i-segmented, short and 

 stubby, very slightly tapering, the apical segment pointed ; segment 

 3<i-f-2, 3>4+5, 3<ii ; scape, pedicel, and first flagellar segment 

 yellow, the other segments light brown. Palpi dark brown to black. 

 Frons, clypeus, and occipital region black, white-pruinose, covered 

 with short black hairs. Cornuae of buccopharyngeal apparatus ex- 

 tremely broad, heavily sclerotized, the ends bifid; median space well 

 sclerotized, with definite central concavity, and with about 23 teeth of 

 variable size that are arranged as follows : 7 short, sharply pointed 

 teeth along border of central concavity ; at each end of concavity there 

 is a projection composed of 3 very long, sharp teeth and 2 shorter 

 teeth ; between each projection and the closest cornua there are 3 

 minute teeth ; the structure of the buccopharyngeal apparatus is sufB- 

 cient to distinguish this species from all other Guatemalan species. 



Thorax : Mesonotum dark brown to black, velvety ; two stripes of 



