NO. I BLACK FLIES OF GUATEMALA — DALMAT 6l 



because of their bloodsucking habits. Pupae are frequently taken with 

 aquatic collections, but they are not often related to the corresponding 

 adults. At the inception of this study, many Guatemalan species were 

 known only in the pupal stage, some only as females, and compara- 

 tively few in the larval form. In order to become acquainted with the 

 simuliid fauna throughout the country, and to be able to distinguish 

 species in whichever developmental stage they may be encountered, 

 specialized methods had to be employed. In general, pupae were col- 

 lected from all types of breeding haunts and held for emergence of 

 the adults. Thus, both sexes of a given species were secured and the 

 pupal skins were available for study along with the cocoons. Larvae 

 were immediately preserved in 70-percent alcohol, 



A method was used whereby pupae and larvae could be transported 

 from the field to the laboratory, or maintained alive in the field for 

 extended periods until it was convenient to arrange them for rearing. 

 The leaves, stems, stones, or other objects, along with their attached 

 pupae and larvae, were placed in a moist canvas bag which permitted 

 cooling by evaporation, thereby facilitating favorable respiratory ex- 

 changes for the immature stages. When convenient, sections of leaves 

 were cut into small pieces so that each piece had a single attached pupa. 

 Each was placed in a small length of glass tubing (:^-inch bore), both 

 ends of which were loosely stoppered with slightly moistened cotton. 

 Pupae formed on small stones were removed and placed in the tube 

 without adding pieces of leaf ; pupae attached to large rocks had to be 

 carefully removed in the field and arranged in the same fashion. The 

 pupae were maintained in the vials for 5 to 7 days, always protected 

 from the direct rays of the sun. The usual method of removing the 

 pupae and placing them on strips of moist cotton was not employed 

 since the cotton seemed to accelerate the formation of mold, and the 

 added handling in unnecessarily removing the pupae from their sub- 

 strata was time-consuming and often caused damage to the pupae. 



After the flies emerged and sufficient time was allowed to elapse for 

 hardening of the cuticula, the adults were pinned on minuten nadeln 

 and the pupal exuvia were preserved in alcohol along with the cor- 

 responding cocoons. Duplicate accession numbers were arranged. 



For each species the following slides were made : Female: (i) Legs, 

 showing the inner and outer surfaces; (2) wings, dorsal and ventral 

 surfaces; (3) head; (4) buccopharyngeal apparatus; and (5) geni- 

 talia, dissected, ventral view, and profile. Male: 1-4 as for female; 

 and (5) genitalia, dissected and dorsal view. Pupa: (i) Dorsal and 

 ventral views ; and (2) respiratory apparatus. Larva: (i) Dissected, 

 dorsal view, ventral view, and profile ; (2) anal gills ; and (3) terminal 



