NO. I 



BLACK FLIES OF GUATEMALA — DALMAT 



19 



than does the reduction in temperature. Beginning usually in October 

 or November, a period of stronger winds is also recorded, this being 

 caused by the winter tradewinds blowing from the northeast. It can 

 be seen that the general climate of the Yepocapa region is mild and 

 rather constant, the only radical changes being in rainfall and, there- 

 fore, in relative humidity. 



Map 8. 



In table 4 comparative annual data are given for six areas within the 

 onchocerciasis zones (Yepocapa, Acatenango, Finca Moca, Finca El 

 Naranjo, Finca El Zapote, and Finca San Luis Buena Vista), for 

 two areas that are not within the disease zones (Acultzingo and Beliz, 

 sections of Finca La Helvetia), although with conditions apparently 

 identical to those within the zones, and for two coastal areas which 

 have ecological conditions quite different from those in the zones. It 

 will be noted that, except for Tiquisate and Bananera, conditions re- 

 ported from all the other regions are somewhat similar. Certain gen- 



