6o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



ing in the same streams were discussed. The developmental cycle of 

 the flies, their oviposition habits, and host preferences were given. 



TAXONOMY OF THE GUATEMALAN SIMULIIDAE 



The species represented in the following systematic treatment were 

 collected in all the 22 Departments of Guatemala. Their distribution, 

 biology, and ecological preferences are discussed in the subsequent 

 section on ecology. 



Keys to the genera, subgenera, and species have been used to intro- 

 duce the taxonomic study. As far as possible, an attempt was made to 

 employ structural characters. In the case of the males, two sets of 

 keys to the genera were presented, as well as to the subgenera of the 

 genus Simulium. Although the genitalia are particularly useful in 

 distinguishing the males in these categories, it was felt that other 

 characteristics should also be given since it may not always be con- 

 venient to use the genitalia. 



The keys have been followed by descriptions of the male, female, 

 pupa, and larva of all species, their completeness depending upon the 

 availability of sufficient material. Descriptions were based only on 

 material collected in Guatemala by the author or other members of 

 the onchocerciasis project, unavailable stages being omitted completely. 

 With few exceptions it was not felt necessary to include in the descrip- 

 tions the characteristics that distinguish the particular species from 

 closely related ones, since this is adequately covered in the keys. When 

 considered desirable, drawings were prepared to illustrate distinctive 

 parts. Those terms used in the keys or in the descriptions that are 

 not in common usage, are not employed in the usual way, or are not 

 figured in the plates, have been diagrammed or defined at the begin- 

 ning of this section. 



No attempt has been made to give complete references to the species, 

 except in the case of those species described after the publication of 

 the catalog of Luis Vargas (1945a) entitled "Simulidos del Nuevo 

 Mundo." This excellent work adequately treats the references to 

 those Guatemalan simuliids known up to that time. However, be- 

 fore giving the description of each species, the reference is given to 

 the paper in which it was originally described, as well as references 

 to other papers that are considered particularly valuable taxonomically. 



TECHNIQUES FOR COLLECTION AND PREPARATION OF 

 MATERIAL 



Adult representatives of the family Simuliidae are only occasionally 

 obtained by the usual collecting techniques, and then only females 



