NO. I 



BLACK FLIES OF GUATEMALA — DALMAT 



ment of the parasites in the flies. His investigations, as well as later 

 ones of Strong (i93ia,b,c), Hoffmann (i93oa,b,c,d,e; 1931a), De 

 Leon (i94oa,b), and Vargas (1948), clearly indicated that Simidium 



' tt.nlmiutP^ 



Fig. I. — Diagrammatic representation of the transmission of human oncho- 

 cerciasis : A, Uninfected Simidium fly biting the infected individual and ingest- 

 ing microfilariae from subcutaneous tissues. B, Infected fly, showing developmen- 

 tal forms of larval filaria in the thorax. C, Developmental form of larval filaria 

 as found in the fly : i, microfilaria ; 2, "sausage" stage ; 3, infective larva. D, Fly 

 with infective larvae infecting a man by his bite. This man will eventually de- 

 velop nodules, as shown in A, in which adult Onchocerca volvulus are found. 



species probably transmit onchocerciasis. This will be discussed in 

 more detail under reservoirs and vectors in the section on "Animal 

 Associations." 



