NO. I BLACK FLIES OF GUATEMALA — DALMAT 87 



with 78 branches in all ; mandible usually with 3 flat teeth on inner margin. 



burchi Dalmat 



Ventrolateral row composed of more than 15 hairs ; posterior sucker with 

 more than 180 rows of hooks ; anal gills with fewer than 78 branches ; inner 



margin of mandible with only 2 flat teeth 6 



6. Postclypeal sclerites almost meeting near midline; ventrolateral row of sub- 

 mentum with 21 hairs; posterior sucker with 184 rows of hooks; 2 flat teeth 

 on inner margin of mandibles arising from common base, .delatorrci Dalmat 



Postclypeal sclerites well separated ; ventrolateral row with only 19 hairs ; 

 posterior sucker with 198-204 rows of hooks; 2 flat teeth of mandibles well 

 separated microbranchium Dalmat 



SPECIES OF THE SUBGENUS LANEA, BASED ON LARVAL CHARACTERS 



1. Posterior sucker with more than 70 rows of hooks 2 



Posterior sucker with 70 or fewer rows of hooks 6 



2. Rectal scales present, arranged in approximately 10 transverse rows ; posterior 



sucker with 105 rows of hooks callidum (Dyar and Shannon) 



Rectal scales absent ; posterior sucker with 71-85 rows of hooks 3 



3. Cephalic fan not pectinate; eighth segment without ventral tubercles. 



jacobsi Dalmat 

 Cephalic fan pectinate ; eighth segment with ventral tubercles 4 



4. Cephalic fan with 37-39 branches, the pectinate hairs very fine and close to- 



gether, with somewhat longer, bifid ones interspersed at regular intervals; 

 apical teeth of submentum long, of varied length, triangular in shape; post- 

 clypeal sclerites well formed and pigmented; several slender, simple spines 

 between anterior and posterior arms of anal sclerite (X-shaped) ; round, 

 raised structure, somewhat green in color, just in front of anterior arms of 



anal sclerite; anal gills with 8-12 branches in all samboni Jennings 



Cephalic fan with more than 40 branches or fewer than 30, the pectinate hairs 

 all of one type; apical teeth of submentum short, all of approximately the 

 same length, pentagonal in shape ; postclypeal sclerites absent or hardly 

 noticeable ; no spines or raised structures in region of anal sclerite ; anal 

 gills usually with total of 3 branches, rarely up to 9 5 



5. Cephalic fan with 27-28 branches, the pectinate hairs all simple ; the two man- 



dibular teeth contiguous to each other, but arising from separate bases ; de- 

 sign on frons-clypeus extending only halfway to anterior margin. 



haematopotitm Malloch 

 Cephalic fan with 42 branches, the pectinate hairs all bifid ; the two mandibular 

 teeth appearing to emerge from the same base; design on frons-clypeus ex- 

 tending to anterior margin dugesi Vargas, Martinez, and Diaz 



6. Cephalic fan with 26-31 branches trivittatum Malloch 



Cephalic fan with more than 32 branches 7 



7. Two flattened teeth on inner margin of mandible arise from common base; 



cephalic fan with 36-42 branches, the fine, short hairs on these branches aris- 

 ing close together, interspersed with heavier, longer hairs at regular 



intervals doimisi Vargas, Martinez, and Diaz 



Two flattened mandibular teeth well separated from eath other ; cephalic fan 

 with 39-49 branches, the pectinate hairs on these branches of one type 

 only 8 



