IV SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 25 



Page 



Ecology 313 



Adult flies 314 



Anthropophilic species 314 



Host preferences 314 



Body regions preferred 315 



Feeding time 317 



Effect of environment on feeding habits 320 



Flight range and longevity 327 



Resting places and height range of the adults 334 



Colonization of black flies 337 



Zoophilic species 341 



Immature stages 342 



Altitude preferences 343 



Stream temperatures in relation to species breeding 346 



pH of streams in relation to species breeding 346 



Width and depth of streams in relation to species breeding 351 



Velocity (current speed) and volume (rate of flow) of streams in 



relation to species breeding 351 



Substratum and stream type in relation to species breeding 363 



Species associations 365 



Relation of oxygen content of streams to species breeding 365 



Relation of dissolved salt to breeding of black flies 366 



Efifect of foreign substances in streams on breeding of black flies. 366 



Ecological notes 366 



Seasonal fluctuation in populations 368 



Natural infection of adults vi^ith Onchocerca volvulus 372 



Transmission of human onchocerciasis in Guatemala 375 



Literature cited 379 



Appendix I : Plants associated with Guatemalan species 387 



Plants associated with woodlands and cultivated areas on 



fincas in onchocerciasis zone 391 



Appendix II : Fauna collected in region of San Pedro Yepocapa 394 



Appendix III : Ecological factors (Table 31 ) 400 



Synoptic life-history chart of the three principal anthro- 

 pophilic species of simuliids of Guatemala (Table 32) . . 400 

 Representation of associated species groups found in 



streams (Table 33) follows 400 



Summary of feeding and resting habits of three species of 



Guatemalan Simuliidae that attack man (Table 34) .... 406 

 Species of Simuliidae attacking various animals, and their 



preferences for different parts of the body (Table 35) . . 406 

 Distribution of Simuliidae according to altitude (Table 



36) 414 



